Geometric Correspondence in the Pacific System: Tectonic-Ring Ellipses, Convection-Roll Boundaries, and Exceptional Tectonic–Volcanic Sites

September 25, 2026October 3, 2026 Steingrimur Thorbjarnarson

Abstract

A comparison of the proposed tectonic-ring geometry with major tectonic and volcanic features around the Pacific suggests that several different types of spatial correspondence should be distinguished. Some geological structures follow the margins of the modeled ellipses, others occur near the ends or extensions of their axes, while still others correspond more closely to the smaller convection-roll boundaries predicted within the upper mantle. The Red Sea, Gulf of California, and Philippine Sea form a particularly useful three-part comparison because each occupies an overlap zone between two of the three large tectonic-ring systems, yet each displays a different tectonic expression. Within the Pacific system itself, San Andreas, Yellowstone, Hawaii, Hikurangi–Alpine Fault, Changbaishan, Galápagos, Izu–Bonin, El Tatio, the Valley of Geysers, and Erebus occupy different but geometrically distinctive positions. The importance of these correspondences lies not in claiming that an ellipse directly creates a rift, fault, volcano, or subduction zone, but in testing whether deep geometrical structures are repeatedly reflected in the location and orientation of independently established geological features.

1. Two superimposed geometrical systems

The analysis requires a distinction between two scales.

The tectonic rings, represented on a mathematical grid.

The first is the tectonic-ring system, represented by large ellipses. In the proposed model these forms are associated with deep mantle organization, ultimately related to the transition near the 670 km discontinuity. Their surface expression should therefore not necessarily be expected to appear as a single fault or volcanic line. Instead, the ellipses may be expressed as broad tectonic margins, curved rift systems, changes in structural regime, volcanic provinces, or zones in which pre-existing lithospheric weaknesses are preferentially reactivated.

The second system consists of the considerably smaller mantle convection rolls. The 2024 Stanford paper defines a family of circular division lines whose centers occur at 1.5° intervals along 32°N. In that analysis, the western edge of the Izu–Bonin system follows the modeled line with $C n = 173.8$ Cn=173.8, beginning near Mount Fuji, while the volcanic chain farther east follows approximately $C n = 175.3$ Cn=175.3. The Izu–Bonin system is about 3° wide, corresponding in the model to two upper-mantle convection rolls.

Thus the two geometries need not have identical surface expressions. A tectonic-ring ellipse may determine the broad position and curvature of a tectonic domain, while convection-roll boundaries may appear more directly as linear or arcuate faults, volcanic chains, ridge segments, or boundaries between tectonic compartments.

This distinction appears repeatedly in the examples considered below.

2. Three corresponding overlap zones

One of the most striking geometrical relationships involves three widely separated regions: the Red Sea, the Gulf of California, and the Philippine Sea region. In the proposed geometry they occupy the three possible pairwise overlaps among the Atlantic, Pacific, and Indian Ocean tectonic-ring systems.

Red Sea — Atlantic–Indian overlap

The Red Sea occupies the overlap between the Atlan ic and Indian Ocean ring systems and closely follows the outer Atlantic ellipse over a long distance.

Its conventional geological interpretation is that of an active continental rift progressing toward oceanic spreading. The important point for the present analysis is not that the ellipse is claimed to have “formed” the Red Sea. Rather, the independently formed rift follows the calculated large-scale curvature of the ellipse unusually well.

The detailed structure adds another level. Individual axial depressions, fracture zones, spreading segments and accommodation zones subdivide the Red Sea. These divisions can be compared with the smaller convection-roll system rather than with the deep ellipse itself. Thus the Red Sea provides an example in which: the ellipse describes the large-scale curved framework, while convection-roll boundaries may correspond to the internal segmentation.

Gulf of California — Atlantic–Pacific overlap

The Gulf of California occupies the corresponding overlap between the Atlantic and Pacific systems and follows the inner Pacific tectonic-ring margin.

Geologically, however, it is not simply another Red Sea. It combines spreading centers with transform faults and connects northward into the San Andreas system. USGS descriptions emphasize precisely this combination of spreading centers and transform displacement south of the San Andreas Fault. The similarity with the Red Sea is therefore geometrical rather than identical in tectonic mechanism.

Both are:

elongated tectonically active zones,
related to plate separation,
strongly segmented,
situated along modeled ellipse margins,
and, in the present geometry, reach a corresponding northern limit close to 32°N.

Philippine Sea — Indian–Pacific overlap

The third overlap zone is fundamentally different. Here a large, distinct plate domain has developed between major convergent boundaries.

The Philippine Sea Plate is unusual in conventional plate tectonics because it is almost completely surrounded by zones of convergence. The Pacific Plate descends beneath its eastern side at the Izu–Bonin, Mariana, and Yap trenches, while the Philippine Sea Plate itself descends beneath Japan and Eurasia along the Nankai–Ryukyu system.

Within the tectonic-ring geometry, the region is particularly interesting because the inner and outer Pacific ellipses form major lateral bounds, while an Indian Ocean ellipse runs obliquely across the broader domain. Thus the three overlap zones are analogous without being duplicates:

Red Sea — extension
Gulf of California — extension plus transform motion
Philippine Sea — predominantly convergence and subduction, with internal back-arc extension

What all three share is not a single tectonic mechanism but the existence of major tectonic boundaries within corresponding ring-overlap sectors.

3. The minor axis of the Pacific ellipse

A second group of relationships emerges from the geometry of the minor axis of the inner Pacific ellipse.

This axis is particularly important because several otherwise unrelated geological features occur at geometrically distinctive positions along it or its continuation.

San Andreas — the northeastern axis end

At one end of the minor axis, the axis reaches the inner Pacific ellipse in the California region.

This is geometrically special because at the end of an ellipse’s minor axis, the tangent to the ellipse is parallel to its major axis. Thus three quantities can be compared independently:

the location of the modeled ellipse,
the tangent direction of the ellipse,
the direction of relative plate motion.

The San Andreas Fault is the transform boundary between the Pacific and North American plates, and the Pacific Plate moves northwest relative to North America.

Consequently, in the model the California location represents more than a simple coincidence between a fault and an ellipse: the plate-motion direction, the major orientation of the fault system, and the local tangent of the ellipse are broadly concordant.

The Gulf of California then continues the tectonic activity southward while following the inner ellipse margin.

Yellowstone — continuation beyond the ellipse

The same minor axis does not terminate geometrically at California. When extended beyond the ellipse, it continues inland toward the Yellowstone volcanic system.

Yellowstone is a large continental volcanic field with three major volcanic cycles during the past approximately two million years; its most recent lava flow is about 77,000 years old.

Thus Yellowstone represents a different category of correspondence:

San Andreas occurs at the axis–ellipse intersection; Yellowstone occurs along the continuation of the same axis beyond the ellipse.

This is important because the model does not require the geological manifestation to remain the same. A transform boundary at one geometrically special point and an intraplate volcanic system farther along the same axis are very different surface expressions.

5. Hawaii — a Central Symmetry Axis in the Convection Roll System

4. Hawaii — a Central Symmetry Axis in the Convection-Roll System

The relationship between Hawaii and the Pacific tectonic-ring system is more complex than a simple correspondence with an axis of an ellipse. Hawaii should not be interpreted as lying on a geometrically defined major or minor axis of the Pacific ellipses. Instead, its significance appears to be connected primarily with the large-scale convection-roll geometry of the lower mantle.

A major set of lower-mantle convection-roll boundaries occupies a central position within the Pacific system. These boundaries are arranged symmetrically on either side of a north–south axis passing through the Hawaiian region. In the model, the principal lower-mantle boundaries on the northern and southern sides of the equator can therefore be regarded as mirror-related across this axis.

The importance of the Hawaiian north–south axis is consequently not derived directly from the mathematical equation of the Pacific ellipses. Rather, it represents a central symmetry line of the underlying convection-roll framework upon which the larger tectonic-ring geometry appears to be superimposed.

A comparable relationship occurs in the other major tectonic-ring systems. In the Atlantic, a principal lower-mantle convection boundary occupies a central position with respect to both the Mid-Atlantic Ridge and the Atlantic tectonic-ring ellipses. A corresponding central relationship can also be identified for the Indian Ocean tectonic-ring system. Thus, in all three cases, the large tectonic ellipses appear to be geometrically organized with respect to major lower-mantle convection boundaries.

This distinction is important. The Pacific ellipses themselves do not provide an obvious direct mathematical reason why Hawaii should occupy its particular position. Instead, the relationship appears at a deeper structural level: the lower-mantle convection-roll boundaries form a central framework, and the tectonic-ring ellipses are arranged relative to that framework.

Hawaii lies close to the north–south symmetry axis of this central Pacific convection-roll structure. This makes its position different from sites such as San Andreas or the Alpine Fault, which are related directly to geometrically distinctive points on the ellipse margins. Hawaii is instead associated with the internal organization of the convection system underlying the entire Pacific ring.

Kīlauea, at approximately 19.4°N, 155.3°W, is one of the most active oceanic volcanoes on Earth. In conventional geological interpretation, Hawaiian volcanism reflects a long-lived mantle hotspot beneath the moving Pacific Plate. Within the present model, the additional observation is that this exceptionally persistent volcanic system occurs close to a major north–south symmetry axis of the modeled lower-mantle convection framework.

The proposed correspondence may therefore be summarized as:

lower-mantle convection-roll boundaries
→ arranged symmetrically around a central N–S axis
→ Hawaii lies close to this axis
→ the same convection framework occupies a central position relative to the Pacific tectonic-ring ellipses.

This type of relationship appears to have analogues in the Atlantic and Indian Ocean ring systems. Hawaii should therefore be regarded not primarily as an “ellipse-axis” feature, but as a possible surface expression associated with the central lower-mantle convection geometry around which the Pacific tectonic-ring system is organized.odel is therefore its relationship to the internal symmetry of the Pacific ellipse, rather than to its rim.

5. New Zealand — the opposite end of the minor axis

The southwestern end of the same Pacific minor axis reaches the New Zealand region, close to the major transition involving the Hikurangi Subduction Zone, Marlborough Fault System, and Alpine Fault.

This is again an independently exceptional tectonic location.

The Alpine Fault forms the major onshore Pacific–Australian plate boundary through the South Island and extends roughly 600 km. The Marlborough fault system transfers plate-boundary motion between the Alpine Fault and the Hikurangi subduction system.

Thus the two ends of the same modeled minor axis correspond to two very different but major plate-boundary systems:

California → San Andreas / Gulf of California

and

New Zealand → Hikurangi / Marlborough / Alpine Fault

The symmetry is geometrical, not tectonic: one side is dominated by transform and extensional motion, the other by a transition between subduction, strike-slip motion, and oblique continental collision.

6. The Pacific–Antarctic geometrical connection

The New Zealand end of the Pacific minor axis also provides a connection to the Antarctic ellipse.

In the model, continuation of this geometry reaches a special point on the minor axis of the Antarctic ellipse. From this Antarctic axis-end another geometrically defined line can be followed northward.

This produces a second major north–south relationship, distinct from the Hawaii central meridian.

Valley of Geysers

The modeled Antarctic-related meridian is close to 160°22.5′E.

The Uzon–Geysernaya volcanic complex and Valley of Geysers in Kamchatka are situated almost exactly in this longitude sector. Smithsonian gives Uzon at approximately 54.49°N, 159.97°E; the Valley of Geysers lies along the eastern part of this volcanic–geothermal complex.

The longitudinal difference from the modeled axis is only about four-tenths of a degree; when latitude is taken into account, the transverse separation is of the order of only tens of kilometres.

This is a particularly interesting correspondence because the Valley of Geysers is one of the world’s most remarkable hydrothermal systems and lies within the highly active Kamchatka volcanic arc.

Erebus

At the Antarctic end, Mount Erebus lies within the same broader geometrical sector. Erebus is the southernmost active volcano on Earth and maintains a persistent summit lava lake.

Its match to the exact north–south line is less precise than that of the Valley of Geysers, and this difference is worth preserving rather than forcing a perfect fit. The important observation is that the Antarctic axis system passes through a region characterized by exceptional volcanism, with Erebus lying nearby.

Thus the Antarctic connection suggests another possible hierarchy:

precise axis correspondence at Valley of Geysers; broader axial-sector correspondence around Erebus and adjacent Antarctic volcanism.

7. Fuji and Izu–Bonin: the convection-roll system becomes dominant

Izu–Bonin is one of the clearest examples showing why the tectonic-ring ellipses and the smaller convection-roll geometry must not be conflated.

The 2024 analysis identifies the western Izu–Bonin boundary with the convection-roll line: $C n = 173.8$ Cn=173.8

which can be followed southward from Mount Fuji. The central volcanic line is associated with approximately: $C n = 175.3.$ Cn=175.3.

The paper notes that the full Izu–Bonin system is about 3° wide, corresponding to two 1.5° upper-mantle convection rolls.

Fuji itself is at 35.361°N, 138.728°E and is a subduction-related stratovolcano; its last known eruption was in 1708.

At the southern end of the larger Izu–Bonin–Mariana system, Challenger Deep enters the model in yet another way: the Stanford analysis associates it with a modeled lower-mantle division line.

Thus this arc provides a particularly useful demonstration of nested geometry:

tectonic-ring framework → broad Pacific setting

lower-mantle division → large arc geometry

upper convection-roll divisions → individual arc margins and volcanic chains

8. Changbaishan — close correspondence with the outer Pacific ellipse

Changbaishan represents another category.

Unlike Fuji, it is not on a simple active oceanic trench–volcanic arc pair. Smithsonian classifies it as an intraplate continental volcano, centered near 41.98°N, 128.08°E. It contains a large summit caldera and a complex basaltic-to-rhyolitic volcanic history.

In the present tectonic-ring calculation, the outer Pacific ellipse passes extremely close to Changbaishan — of the order of only a few tens of kilometres.

This is therefore best classified as an ellipse-margin correspondence, rather than a convection-roll example.

Its importance lies precisely in its unusual tectonic context: a major volcanic center that is not simply situated on the main Pacific trench.

9. El Tatio — superposition of two influences

El Tatio in northern Chile is another distinctive example, but the match is less exact.

The geothermal field lies at approximately 22.33°S, 68.01°W, within the Central Andes volcanic environment generated by Nazca–South America convergence. It consists of numerous geysers, hot springs, fumaroles, and other hydrothermal manifestations.

The outer Pacific ellipse passes through the same broad sector but does not run directly through El Tatio; our calculation places El Tatio roughly 150–160 km from the modeled ellipse line.

This is therefore not best presented as a precise ellipse intersection.

Instead, El Tatio may be a particularly useful example of superposition:

a broad positional influence related to the Pacific tectonic-ring margin combined with more local control from the upper-mantle convection-roll geometry.

This interpretation is especially relevant because the 2024 analysis already finds extensive correspondence between modeled upper-mantle rolls and the distribution of South American volcanic arcs and their subdivision into individual segments.

In other words, the ellipse may determine the broader tectonic corridor while the smaller convection rolls more closely determine where individual volcanic or geothermal systems occur.

10. Galápagos — an intersection of two inner ellipses

Galápagos may be among the most geometrically distinctive sites considered here.

In the present calculations, the inner Pacific tectonic-ring ellipse and the inner Atlantic tectonic-ring ellipse intersect close to the equator at approximately 92.3°W. This places their intersection immediately west of the Galápagos archipelago. Fernandina, the westernmost major island, lies at 0.37°S, 91.55°W and is the most active Galápagos volcano and the one nearest the Galápagos mantle-plume center.

Galápagos is also located near the Galápagos Spreading Center, where new oceanic crust is produced between the Cocos and Nazca plates. USGS notes that the spreading center and its fracture systems have interacted with the hotspot and have influenced the development of the archipelago. Consequently, Galápagos is not merely “near the Pacific ellipse.” It represents a more specific geometry:

inner Pacific ellipse
× inner Atlantic ellipse
≈ Galápagos hotspot–ridge interaction zone.

This makes Galápagos analogous to the other ellipse-intersection regions discussed earlier, but on a smaller and exceptionally volcanic scale.

11. A hierarchy of geometrical correspondences

These examples suggest that it is useful to stop treating all matches as equivalent. At least six distinct classes can be recognized.

Ellipse-margin correspondence is represented by the Red Sea, Gulf of California, Changbaishan, and parts of the Andean system.

Ellipse-overlap correspondence appears in the Red Sea, Gulf of California, and Philippine Sea comparison.

Axis-end correspondence occurs at San Andreas and the Hikurangi–Alpine Fault region.

Axis-extension correspondence includes Yellowstone and the continuation connecting the Pacific and Antarctic systems.

Central-meridian correspondence characterizes Hawaii.

Ellipse-intersection correspondence is illustrated especially well by Galápagos.

A seventh type is then required:

ellipse–convection-roll superposition, of which El Tatio may be a useful example.

Finally, the Izu–Bonin system demonstrates direct convection-roll correspondence, where the smaller roll geometry appears more important than the large ellipse itself.

12. Why the different tectonic expressions matter

The geology of these sites is extraordinarily diverse.

San Andreas is a transform boundary.
Yellowstone is a continental volcanic field.
Hawaii is an oceanic hotspot chain.
Hikurangi is a subduction zone.
The Alpine Fault is a major oblique strike-slip plate boundary.
Izu–Bonin is an oceanic subduction arc.
Changbaishan is classified as an intraplate volcano.
El Tatio is an Andean geothermal system.
Galápagos combines hotspot volcanism and nearby seafloor spreading.
The Valley of Geysers is a subduction-related geothermal system.
Erebus is an active Antarctic volcano.

Their conventional geological explanations therefore remain different.

The proposed importance of the ellipse framework is not that all these features must have the same immediate cause.

Instead, the hypothesis is that a deeper, large-scale mantle geometry may influence where different tectonic processes are preferentially expressed, while plate motion, lithospheric inheritance, slab geometry, crustal thickness, local stresses, and shallower convection determine the form that the surface response ultimately takes.

This could also explain why some correspondences are remarkably sharp while others are diffuse.

A shallow convection-roll boundary might generate a relatively precise structural alignment. A geometry rooted hundreds of kilometres deeper may be expressed over a considerably broader surface belt.

13. From visual correspondence to a quantitative test

The strongest way to develop this analysis further is therefore not to demand perfect correspondence at every locality. Instead, each predicted feature can be assigned to its geometrical class before comparing it with the geology.

For example:

San Andreas: distance from minor-axis endpoint + angle between plate-motion vector and ellipse tangent.

Yellowstone: perpendicular distance from extended minor axis.

Hawaii: Centrally located lower mantle convection rolls divisions.

Hikurangi–Alpine: distance from the opposite minor-axis endpoint.

Valley of Geysers: distance from the Antarctic-derived N–S axis.

Changbaishan: shortest distance to the outer Pacific ellipse.

El Tatio: distance to ellipse plus distance to the relevant upper convection-roll boundary.

Galápagos: distance from the calculated intersection of the inner Pacific and Atlantic ellipses.

Fuji–Izu–Bonin: distance from the predicted $C n = 173.8$ Cn=173.8 and $C n = 175.3$ Cn=175.3 convection-roll curves.

This approach would make it possible to distinguish genuinely precise matches from broad regional ones and would considerably strengthen the argument by avoiding the impression that geological locations were selected first and geometrical lines fitted afterwards.

Conclusion

Taken individually, any one correspondence could be accidental. Taken together, however, the locations form a structured set that deserves systematic testing.

The three great overlap zones — Red Sea, Gulf of California, and Philippine Sea — all coincide with major tectonic boundaries despite their very different tectonic expression.

Within the Pacific ellipse itself, the minor axis connects San Andreas, the central geometry associated with Hawaii, and the Hikurangi–Alpine region, while its extension relates to Yellowstone and continues geometrically toward the Antarctic system.

The Antarctic axis geometry in turn leads toward the Valley of Geysers and passes through an Antarctic volcanic sector that includes Erebus.

Elsewhere, Changbaishan closely approaches the outer Pacific ellipse, El Tatio appears compatible with superimposed ellipse and upper-roll influences, and Galápagos occupies an especially notable intersection of the inner Pacific and Atlantic ellipse margins.

Finally, Fuji–Izu–Bonin–Mariana demonstrates that the smaller convection-roll system can produce a much more precise surface alignment than the deep ellipses themselves, consistent with the distinction between broad deep-mantle geometry and shallower structural control developed in the model. The 2024 Stanford analysis explicitly identifies the Izu–Bonin arc, South American volcanic zones, and other Pacific subduction systems as tests of this finer convection-roll geometry.

The emerging picture is therefore not of a single ellipse “creating” faults or volcanoes. It is of a nested geometrical framework in which ellipse margins, axes, axis extensions, intersections, and smaller convection-roll boundaries correspond to different levels of tectonic organization. That distinction may be essential for understanding why the model sometimes produces an exceptionally precise match and elsewhere appears only as a broader regional influence.

Uncategorized

Framing the Philippine Sea Plate

September 23, 2026September 25, 2026 Steingrimur Thorbjarnarson

The Philippine Sea Plate is one of the smaller major tectonic plates of the Earth. It is surrounded by a complex system of plate boundaries and microplates, but in broad terms it occupies the region between the Eurasian Plate to the west, the Pacific Plate to the east, and the Australian Plate to the south.

Location of Cahallenger Deep and Fuji pointed out.

When the geometry of the Pacific Ring of Fire is analysed within the convection-roll model, an additional spatial framework emerges. The tectonically active margins surrounding the Pacific appear, in this model, to be largely confined within zones corresponding to the influence of convection-roll systems 15° wide on either side of the Pacific basin, of approxiamately 19.5°.

This produces a regular geometrical framework defined by elliptical forms. The principal Pacific ellipse is centred at approximately 6°S, 150.7°E and is rotated by about 45° when plotted on an equidistant rectangular map. Its geometry is related to a larger elliptical system extending toward the South Pole. Two corresponding elliptical systems can then be positioned at intervals of 120° in longitude, producing three major tectonic-ring frameworks around the Earth.

The geometry is constrained by fixed parameters. In the coordinate system used here, the inner ellipse has a minor semiaxis of 51.8 units and a major semiaxis of 77.7 units, whereas the outer ellipse has corresponding values of 71.0 and 96.5 units. Once these parameters, centres, and orientations have been fixed independently, the resulting framework can be compared with observed geological structures without further adjustment.

The Philippine Sea Plate at the Intersection of Two Tectonic Rings

One particularly interesting comparison concerns the Philippine Sea Plate. Within this geometrical framework, the plate occupies the intersection between the Pacific tectonic ring (the Ring of Fire) and the neighbouring tectonic ring associated with the Indian Ocean.

The basic shape and location of the Philippine Sea Plate.

The Philippine Sea Plate fits remarkably regularly within this intersection zone. In simplified geometrical form, it can be represented as a diamond-shaped region whose southern apex approaches the Equator. Its eastern and western margins broadly follow the structural directions generated by the intersecting ring systems, while its northern termination lies within the complex tectonic region of Japan.

Several individual features provide useful reference points for testing the geometry. The inner margin of the Indian Ocean tectonic ring reaches the Mariana–Philippine Sea boundary close to the Challenger Deep, the deepest known point in the world’s oceans. This is situated along the boundary between the Philippine Sea Plate and the Pacific Plate. Farther north, Mount Fuji lies close to one of the principal convection-division lines defined by the model.

The geometry also highlights the possible structural significance of particular latitudes. The Equator forms an important southern reference line, while approximately 32°N provides a northern geometrical boundary within the model. Much of the Philippine Sea Plate is therefore contained between these two latitude controls.

A second regularity appears in longitude. North–south axes can be defined at intervals related to the 15° convection-roll spacing, together with an additional half-spacing of 7.5°. This gives a characteristic east–west interval of approximately 22.5°, comparable with the longitudinal width of the plate and its surrounding tectonic system.

A Geometrically Constrained Plate

The significance of the Philippine Sea Plate in this analysis is therefore not based on a single point of correspondence. Several independent geometrical elements can be compared simultaneously: the Equator, the 32°N latitude, the north–south convection divisions, the margins of the two intersecting tectonic rings, the position of the Mariana Trench and Challenger Deep, and the northern tectonic junction near Japan.

Taken together, these relationships make the Philippine Sea Plate a particularly useful area for testing the tectonic-ring model. Instead of appearing as an irregular plate whose shape is considered only in relation to its immediate neighbouring plates, it can be examined as a structure occupying a geometrically defined intersection between two larger-scale tectonic systems.

The most striking feature is therefore the overall confinement of the Philippine Sea Plate within the overlapping domains of the Pacific and Indian Ocean tectonic rings. If this correspondence remains consistent when tested against independently mapped plate boundaries, trenches, volcanic arcs, and seismic zones, the Philippine Sea region may provide one of the clearest examples for evaluating the proposed global convection-roll framework.

Further reading: https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2024/Thorbjarnarson.pdf

Challenger Deep: A Convergence of Geometrical and Tectonic Features

A particularly significant location within this framework is the Challenger Deep, because several of the geometrical relationships investigated in this study converge within a very small area. Challenger Deep is located near 11°22′N, 142°30′E, at the southern end of the Mariana Trench. Modern measurements place its greatest depth at approximately 10,935 ± 6 m below mean sea level, making it the deepest reliably measured point in the world’s oceans.

In conventional plate-tectonic terms, Challenger Deep forms part of the Izu–Bonin–Mariana subduction system. Along this system, the Pacific Plate descends westward beneath the plate system forming the eastern margin of the Philippine Sea region. At the southern Mariana Trench, the immediate overriding plate is the Mariana microplate, separated farther west from the main Philippine Sea Plate by the Mariana Trough. Thus, Challenger Deep occupies a highly distinctive position along the eastern tectonic boundary of the broader Philippine Sea Plate system.

Within the convection-roll and tectonic-ring model presented here, however, the location acquires an additional geometrical significance.

The eastward-bending convection roll centred at approximately 113.8°E, with its geometry referenced to 32°N and a radius of 35.341 model units, intersects the inner elliptical margin of the Indian Ocean tectonic ring almost exactly in the Challenger Deep region. The Indian Ocean ring is defined here by a centre at approximately 90.7°E, 6°S, with an inner ellipse having semiaxes of 51.8 and 77.7 model units and an orientation of approximately 45° NW–SE.

Because these geometrical parameters are established independently of the position of Challenger Deep, the correspondence provides a useful test of the proposed framework rather than a geometrical construction fitted specifically to the trench.

A second convection-roll structure also approaches this location. The westward-bending roll centred at approximately 173.8°E, which passes beneath the Fuji region farther north, intersects the 113.8°E roll system only about 2° of map distance from Challenger Deep. The proximity of this lower-mantle roll intersection to the deepest part of the Mariana Trench is therefore another feature that can be tested against the model.

These roll intersections are also associated in the model with major north–south structural axes. Comparable axes can be traced northward from Antarctica, and one of these axes closely follows the eastern side of the Philippine Sea Plate system. Challenger Deep consequently lies close not only to a plate boundary and an elliptical ring margin, but also to one of the principal N–S divisions generated by the convection-roll geometry.

A fourth geometrical element occurs immediately to the east. The inner margin of the Pacific tectonic ring (the Ring of Fire) lies only about 3° east of Challenger Deep. Southeast of the Challenger Deep region, this Pacific-ring margin approaches and eventually intersects the inner margin of the Indian Ocean tectonic ring. Challenger Deep is therefore situated close to the area where the influence zones of two independently defined tectonic rings converge.

The location can consequently be described in terms of several superimposed geometrical controls:

the active Pacific–Mariana subduction boundary;
the inner margin of the Indian Ocean tectonic ring;
the nearby inner margin of the Pacific Ring of Fire;
the intersection of two convection-roll systems;
and a major N–S structural axis associated with the convection-roll framework.

The morphology of Challenger Deep itself may also be relevant. Rather than forming one simple linear depression, its deepest region consists of several elongated depressions arranged in a broadly right-stepping en echelon pattern. Such segmentation suggests that the morphology of the trench cannot necessarily be described solely in terms of motion perpendicular to the subduction boundary. Along-strike deformation, oblique stresses, inherited structures, and deformation within the overriding and subducting plates may also contribute to its detailed form.

Within the model proposed here, this geometry raises an additional possibility. The Mariana subduction system represents the dominant conventional tectonic process operating at the site, while the elliptical tectonic-ring boundaries describe predominantly horizontal, large-scale geometrical controls. The convection-roll divisions, in contrast, represent vertically organised mantle circulation expressed at the surface through their predicted boundaries and intersection zones.

Challenger Deep may therefore represent an especially useful location for examining the proposed interaction between these two components: horizontal tectonic organisation associated with the elliptical ring system and vertically organised mantle circulation associated with the convection rolls. Their spatial coincidence with an active subduction zone could help explain why this particular part of the plate boundary has developed such an exceptional and strongly segmented morphology.

This does not by itself demonstrate a causal relationship between the geometrical framework and the exceptional depth of Challenger Deep. It does, however, provide a particularly well-constrained location at which several independently derived elements of the model can be compared directly with observed bathymetry, plate boundaries, seismicity, and subduction geometry.

According to the present model, Challenger Deep is located at a point where two independently defined structural controls coincide. The inner margin of the tectonic ellipse passes through the area, while a convection-roll division derived from a different part of the model also intersects the same locality. Their orientations are therefore not merely spatially close; they form a superimposed geometrical framework at the site.

This suggests that several tectonic components may be acting together. The Mariana subduction system provides the dominant convergent setting, while the regional oblique plate motion introduces a significant strike-slip component. Superimposed on this, the model places both an elliptical tectonic boundary and a convection-roll division through the Challenger Deep region. The morphology of the deep may therefore reflect the combined influence of convergence, lateral shear, and the interaction of these two larger-scale structural controls.

In this interpretation, Challenger Deep becomes especially significant because the different elements are derived independently. The elliptical geometry is defined by the tectonic-ring framework, whereas the convection-roll directions are determined by the mantle-roll system. Their intersection at the same location, together with the observed trench and strike-slip geometry, provides a particularly useful site for testing whether these proposed controls are reflected in the actual structure of the plate boundary.

Uncategorized

The Red Sea and the Gulf of California: Two Comparable Rift Systems

September 20, 2026September 21, 2026 Steingrimur Thorbjarnarson

According to the tectonic-ring model associated with the mantle convection-roll system, the Red Sea and the Gulf of California occupy remarkably similar geometrical positions.

The position of Red Sea and Gulf of California as compared with the scope of the Ring of Fire
and the other theoretical tectonic rings of the Atlantic and Indian oceans.

Both form elongated zones of crustal extension situated along the margins of large tectonic rings, although they occur on opposite sides of the global system.

The Red Sea

In the model, the Red Sea is situated along the outer periphery of the Atlantic tectonic ring, which is theoretically derived as the counterpart of the Pacific Ring of Fire. Its elongated form follows the curvature of the corresponding elliptical boundary.

On the map, 32°N latitude is shown as a reference line and marks the northern limit of the section highlighted in red. From there, the tectonically active zone extends southward toward the Afar region, where the Red Sea system connects with the Gulf of Aden and the East African Rift.

The Gulf of California

The Gulf of California occupies a comparable position along the inner periphery of the Pacific tectonic ring, or Ring of Fire. As in the Red Sea, the elongated tectonic zone approximately follows the geometry of the relevant elliptical boundary.

Again, 32°N latitude is shown as a reference, allowing the geographical positions of the two systems to be compared directly. The Gulf of California extends southward from approximately this latitude and forms part of the active boundary between the Pacific and North American plates.

A striking geometrical comparison

Comparison of the two regions reveals several noteworthy similarities:

Both form long, narrow tectonic basins produced by crustal extension.
Both are associated with active plate separation and magmatism.
Both occupy marginal positions within the proposed tectonic-ring geometry. The Red Sea follows the outer boundary of the Atlantic ring, whereas the Gulf of California follows the inner boundary of the Pacific ring.
The highlighted sections occupy broadly comparable latitude ranges and can therefore be compared directly using the 32°N reference line.
Both systems developed mainly during the Cenozoic and underwent major tectonic reorganization during the Miocene and later.
In both cases, extension is not expressed as a single simple fracture. Instead, deformation is distributed through rift basins, faults, volcanic zones, and, in more developed sections, spreading centres.

The similarity is particularly interesting because the two systems belong to different conventional plate-tectonic settings. The Red Sea records the separation of Arabia from Africa, whereas the Gulf of California forms part of the Pacific–North America plate boundary. Nevertheless, when viewed within the tectonic-ring framework, both occupy equivalent geometrical positions along major elliptical boundaries. The precondition of this comparison is of course at first to analyse the form of the Ring of Fire, and the to transfer that analysis to the Atlantic Ocean.

Possible significance

The comparison therefore raises an important question: can the similar geometry of the Red Sea and the Gulf of California be explained solely by their individual plate-tectonic histories, or does their position within a larger global geometrical system also play a role?

Within the convection-roll model, the resemblance is not regarded as accidental. The two regions can be interpreted as corresponding expressions of extension along the boundaries of two different tectonic rings: one on the outer side of the Atlantic ring and the other on the inner side of the Pacific ring.

Their similar elongated forms, broadly comparable latitudinal positions, young geological development, and relationship to active extension make the Red Sea–Gulf of California comparison a useful test case for examining the proposed connection between mantle convection rolls and the large-scale geometry of plate boundaries.

Uncategorized

Comparison Between Earthquake Zones and the Convection-Roll Model

September 18, 2026September 18, 2026 Steingrimur Thorbjarnarson

When the distribution of earthquake epicentres in Iceland during the period 1994–2007 is compared with the surface pattern predicted by the convection-roll model, a considerable degree of spatial correspondence becomes apparent.

The relationship takes somewhat different forms in different parts of the country. Across southern Iceland, much of the seismicity is concentrated within, along the margins of, or near the corners of the diamond-shaped sectors formed by the division lines of the model. North of Iceland, the pattern is different: within the Tjörnes Fracture Zone, earthquake epicentres tend to form elongated belts that can be compared directly with individual division lines.

Several examples illustrate this relationship particularly clearly.

1. The Reykjanes Ridge and the Njörður area

At this location, the Reykjanes Ridge, as an oceanic spreading ridge, meets an offshore structural system transverse to the ridge. A marked concentration of earthquake epicentres occurs close to this intersection.

The area is also associated with Njörður, a large submarine central volcano situated on the Reykjanes Ridge. Within the convection-roll framework, the concentration of tectonic and volcanic activity near this location is significant because it occurs close to an intersection between major division lines.

2. The curved seismic belt of the Reykjanes Peninsula

The earthquake belt extending across the Reykjanes Peninsula does not form a simple straight continuation of the Reykjanes Ridge. Instead, it bends progressively eastward toward the Hengill–Hveragerði region.

Within the convection-roll model, this geometry can be interpreted as a connection between the offshore Reykjanes Ridge and the Western Volcanic Zone. The two principal connection points are not located at the same latitude, and the complete seismic system consequently extends across two adjoining diamond-shaped sectors.

Of particular interest is that the curvature of the seismic belt from the Njörður area toward Hveragerði can be represented by the same mathematical arc used to construct the corresponding division line in the model.

3. Hveragerði and the Hengill region

The Hveragerði–Hengill region is one of the most seismically active areas of southwestern Iceland.

In the convection-roll model, this is not merely a minor intersection between division lines. It represents a principal intersection associated with the lower-mantle framework, where division systems derived from the polar and equatorial geometries converge.

The model therefore places an unusually important structural intersection close to Hveragerði and Reykjafell. The high concentration of earthquake epicentres in this area is consequently one of the more conspicuous spatial correspondences between the calculated geometry and observed seismicity.

4. The South Iceland Seismic Zone

The South Iceland Seismic Zone provides another particularly clear example. Earthquake epicentres are concentrated in a broadly east–west belt extending between the western and eastern corners of one of the model’s diamond-shaped sectors. The main trend extends approximately from the Hveragerði region toward Hekla, close to 64°N.

Thus, rather than following only a single division line, the seismicity occupies the interior of a geometrically defined sector and is particularly concentrated between its opposing corners.

5. Torfajökull

East of the main South Iceland Seismic Zone lies the Torfajökull volcanic system. This area can be regarded both as a distinct volcanic and geothermal region and, in geometrical terms, as an eastward continuation of the structural pattern associated with the South Iceland Seismic Zone. The concentration of earthquake epicentres around Torfajökull again occurs within a sector defined by the division-line geometry.

6. Eyjafjallajökull and Mýrdalsjökull

Farther south, earthquake clusters coincide with the volcanic systems of Eyjafjallajökull and Mýrdalsjökull, including the Katla caldera beneath Mýrdalsjökull. An additional feature is the approximately east–west arrangement of seismicity across the central part of the corresponding diamond-shaped sector. The relationship therefore involves both the location of the volcanic centres and the internal geometry of the sector itself.

7. Grímsvötn

The Grímsvötn area beneath Vatnajökull is one of Iceland’s most active volcanic regions. On the earthquake map, much of the seismicity in this region falls within the same diamond-shaped sector predicted by the convection-roll model. The concentration is therefore not restricted to a single line or intersection; instead, the active region occupies a substantial part of one geometrically defined cell.

8. Bárðarbunga

Bárðarbunga forms another major concentration of volcanic and seismic activity beneath northwestern Vatnajökull. Its caldera and associated fissure system lie within the same broader geometrical framework. The seismicity around Bárðarbunga therefore provides an additional test of whether the division lines and the diamond-shaped sectors have a systematic relationship with the distribution of tectonic and volcanic activity.

9. Askja and the northeast-trending fissure swarm

The Askja region forms a distinct seismic and volcanic centre farther north. From Askja, earthquake activity extends northeastward along the associated fissure swarm. In the convection-roll interpretation, both the location of Askja and the orientation of this northeast-trending seismic zone correspond with the underlying division-line pattern.

This is important because the comparison involves not only the position of an individual volcanic centre but also the direction in which tectonic activity extends away from it.

10. The Húsavík–Flatey Fault

North Iceland provides a different type of comparison. The Húsavík–Flatey Fault (HFF), one of the principal structures of the Tjörnes Fracture Zone, is marked by a pronounced belt of earthquake activity. Within the convection-roll model, this belt follows one of the calculated division-line trends remarkably closely.

Toward the western part of the Tjörnes Fracture Zone, the orientation of the seismicity changes as the system approaches the connection with the Kolbeinsey Ridge. This change occurs close to an area where division lines of the convection-roll framework also intersect and change their geometrical relationship.

The importance of this example is therefore twofold: the earthquake belt follows a predicted division-line direction over a considerable distance, while its change in geometry also occurs close to a significant intersection in the model.

11. The Grímsey Oblique Rift

The Grímsey Oblique Rift (GOR) forms the second major seismic belt of the Tjörnes Fracture Zone. Its orientation corresponds closely to the next division line to the north in the convection-roll framework. The earthquake epicentres do not form an infinitely narrow line, but rather a relatively broad zone extending mainly northward from the calculated boundary.

The width of this seismic zone corresponds approximately to two adjacent convection-roll sectors. A comparable relationship can be observed along the Húsavík–Flatey Fault, suggesting that the influence of the structural boundaries may extend across more than a single line.

Different Forms of Spatial Correspondence

The comparison between the 1994–2007 earthquake distribution and the convection-roll framework is therefore not based on one particular type of geometrical relationship. At least three recurring forms can be distinguished.

First, major concentrations of seismicity occur near intersections of division lines, as seen particularly in the Hveragerði–Hengill region and offshore along the Reykjanes Ridge.

Second, earthquake activity may occupy or follow the internal geometry of diamond-shaped sectors, as seen across southern Iceland from the South Iceland Seismic Zone through the central volcanic regions.

Third, elongated seismic zones may follow individual division lines, as is particularly evident in the Tjörnes Fracture Zone, including the Húsavík–Flatey Fault and the Grímsey Oblique Rift.

The significance of the comparison therefore lies not simply in individual earthquake clusters coinciding with individual calculated lines. Rather, similar geometrical relationships appear repeatedly in different tectonic settings: at volcanic centres, within seismic zones, at major intersections, and along long linear fault and rift systems.

This repeated spatial correspondence provides a basis for testing whether the surface geometry derived from the convection-roll model is related in a systematic way to the distribution of seismic and volcanic activity in Iceland.

Uncategorized

A 30° Equatorial Sequence of Major Tectonic and Geographic Features

September 17, 2026 Steingrimur Thorbjarnarson

30° stepstones along the equator (yellow dots).

A particularly striking feature of the proposed mantle-convection framework is a regular sequence of principal lower-mantle divisions along the equator. Taking 21.16°W as the theoretical reference longitude beneath the central Atlantic, equivalent divisions occur at intervals of exactly 30°. Moving eastward around the Earth, the relevant sequence considered here is:

111.16°W — East Pacific Rise
81.16°W — western margin of South America
51.16°W — Amazon mouth and northeastern South America
21.16°W — central Atlantic / Mid-Atlantic Ridge
8.84°E — western coast of equatorial Africa
38.84°E — East African Rift region
68.84°E — Central Indian Ridge
98.84°E — western margin of Indonesia
128.84°E — eastern Indonesia
158.84°E — possible additional boundary east of Papua New Guinea

These are theoretical longitudes. The model does not require the principal surface expression to occur precisely on each lower-mantle division. Upper-mantle upwelling lines occur approximately 1.5° to either side, while the effects of the adjacent convection roll may be expressed as much as 3° from the principal division. The appropriate comparison is therefore with a narrow longitudinal belt rather than with a geometrically infinitesimal line.

1. 111.16°W — East Pacific Rise

The first point lies in the eastern Pacific and corresponds closely to the East Pacific Rise, one of the Earth’s major oceanic spreading systems. Around the equatorial and southeastern Pacific, the East Pacific Rise occupies approximately the 110°W region, although its longitude varies with latitude. The theoretical longitude of 111.16°W therefore falls within about one degree of the broad ridge system. Studies of the eastern tropical Pacific commonly place the Rise near 110°W, while the EPR can be followed continuously southward from the equatorial region.

This is an important starting point because here the expected mantle division is expressed by an unmistakable oceanic spreading system. In the convection-roll interpretation, the surface ridge need not coincide exactly with the lower-mantle division; displacement toward an adjacent upper-mantle upwelling line would be expected.

2. 81.16°W — the western margin of South America

Thirty degrees farther east gives 81.16°W. At the equator this lies immediately west of the coast of Ecuador. Ecuador itself straddles the equator and its western boundary is the Pacific continental margin.

This is a fundamentally different tectonic environment from the East Pacific Rise. Instead of oceanic spreading, the eastern Pacific basin terminates against the South American margin, where the Nazca Plate converges with South America. Thus, within one 30° interval, the system passes from a major zone of crustal production to the continental margin toward which that oceanic plate moves.

The correspondence should not be interpreted as a claim that 81.16°W itself is the trench axis. Rather, it marks the equatorial longitude of the broader western South American tectonic boundary zone.

3. 51.16°W — the mouth of the Amazon

The next theoretical division, 51.16°W, reaches the opposite side of South America near the great outlet of the Amazon River.

This point is different from most of the others because the dominant surface expression is not an active plate boundary. Nevertheless, the Amazon mouth marks one of the major geological and physiographic transitions on Earth: the enormous Amazon drainage system reaches the Atlantic margin here. NASA describes the Amazon as carrying the largest freshwater discharge of any river, delivering roughly one fifth of global river discharge to the oceans.

Within the proposed framework, the significance would therefore not necessarily be present-day faulting. The question is whether the continental-scale drainage architecture, sedimentary basin and Atlantic continental margin preserve a longer-term structural influence associated with the same regular mantle division.

This point consequently needs to be treated more cautiously than the active ridges and rifts.

4. 21.16°W — the central Atlantic

Another 30° east brings the sequence to its reference point, 21.16°W.

This correspondence is particularly close. The Mid-Atlantic Ridge crosses the equatorial Atlantic in the vicinity of 21–22°W. For example, a large 2022 earthquake classified by the USGS as occurring on the central Mid-Atlantic Ridge was located at 0.934°S, 21.716°W. The theoretical value of 21.16°W is therefore within roughly half a degree of this active ridge position.

In the model, this longitude represents a principal lower-mantle division, while the actual surface spreading system may occupy the adjacent 1.5° roll positions. This distinction is important: the geometric reference is defined at depth, while the observable ridge records the response of the upper mantle and lithosphere.

5. 8.84°E — western equatorial Africa

The next 30° step gives 8.84°E, which reaches the Atlantic coast of equatorial Africa near Gabon. Independent geographical data place the equatorial portion of Gabon between approximately 9°E and 14°E, making 8.84°E essentially a coastal or immediately offshore position. Thus the 30° sequence produces another striking basin-scale relationship:

South American Atlantic margin → Mid-Atlantic Ridge → African Atlantic margin, at intervals of approximately 30°.

This does not mean that the Atlantic basin is geometrically symmetrical in conventional plate-tectonic terms. Rather, it suggests that the theoretical mantle sequence intersects three very different parts of the Atlantic system: one continental margin, the spreading axis, and the opposite continental margin.

6. 38.84°E — the East African Rift region

The next theoretical lower-mantle division is 38.84°E. Here the distinction between the lower-mantle division and the surface response becomes particularly important. The main Kenya Rift at the equator does not lie at 38.84°E. Its axial region is farther west. Lake Bogoria, for example, lies at approximately 36.05–36.12°E immediately north of the equator, within the central Kenya Rift. However, the model predicts:

38.84°E — principal lower-mantle division
37.34°E — upper-mantle upwelling line
35.84°E — outer influence/downwelling side of the adjacent 1.5° roll

The last value, 35.84°E, falls remarkably close to the active Kenya Rift. The central Kenya Rift itself is a roughly 100-km-wide asymmetric extensional structure in this region.

Seismic and gravity studies along the equator have additionally suggested that the elevated East African plateau requires a regional mantle contribution and is compatible with dynamic support by mantle convection. This makes the African point particularly useful for distinguishing the deep theoretical division from its displaced lithospheric expression.

7. 68.84°E — the Central Indian Ridge

Thirty degrees farther east lies 68.84°E, almost directly on the active ridge system of the central Indian Ocean. The Central Indian Ridge extends northward from the Rodrigues Triple Junction toward the Carlsberg Ridge. Near the equatorial region it lies broadly between 67°E and 69°E. Published ridge-axis locations include approximately 1.19°S, 67.52°E, and farther south several segments occur between about 68.1° and 68.6°E.

The theoretical 68.84°E position therefore falls comfortably within the ±1.5° influence interval and extremely close to the actual spreading system.

Together with the Mid-Atlantic Ridge and East Pacific Rise, this gives the sequence three major oceanic spreading systems separated by intervening continental and tectonic domains.

8. 98.84°E — western Indonesia

At 98.84°E, the sequence reaches the western Indonesian region, close to Sumatra and the Sunda convergent margin.

This is no longer a spreading environment. Southwest of Sumatra, the Indo-Australian plate converges with the Sunda plate along the Sunda–Java trench system. The USGS describes this as part of an immense collision zone extending from the Indonesian region toward the Himalaya and notes the intense seismicity and volcanism produced by the Sumatra–Andaman subduction system.

The theoretical longitude therefore lies near one of the Earth’s major transitions from Indian Ocean lithosphere into the Indonesian convergent system.

9. 128.84°E — eastern Indonesia

Another 30° east gives 128.84°E, in the exceptionally complex tectonic region of eastern Indonesia, close to the Molucca Sea–Halmahera system.

This is one of the most unusual convergent environments on Earth. The Molucca Sea plate has been consumed by oppositely directed subduction beneath the Sangihe and Halmahera arcs, producing an active arc–arc collision. Modern studies describe the Molucca Sea as one of Southeast Asia’s most complicated tectonic regions and document the interaction of the Philippine Sea, Eurasian/Sunda and Australian plate systems.

A USGS regional tectonic map of the central Molucca Islands uses 128°E as its central meridian and shows subduction zones, strike-slip faults, thrusts and volcanic arcs concentrated through this longitude range. Thus the 128.84°E point corresponds not merely to the eastern edge of Indonesia geographically, but to a major zone of tectonic reorganisation.

10. 158.84°E — a possible additional point east of Papua New Guinea

The next step, 158.84°E, is particularly interesting because it lies east of Papua New Guinea in the Woodlark–Solomon region. This point has not yet been incorporated into the principal sequence in the same way as the preceding nine because the geological relationships are much more complicated. Nevertheless, there is clearly major tectonic and magmatic activity within the predicted belt.

The USGS places the Woodlark Basin between approximately 157° and 159.5°E, directly encompassing the theoretical longitude of 158.84°E. The basin contains the boundary between the Solomon Sea and Australian/Woodlark plates and is an active extensional system. Immediately farther east, the Guadalcanal segment of the Solomon plate boundary occupies approximately 159–161°E.

The broader Solomon system combines active seafloor spreading, subduction of young Woodlark lithosphere, microplate motion, intense seismicity and interaction with the Ontong Java Plateau. The USGS tectonic synthesis shows spreading across the Woodlark Ridge and subduction along the Solomon system, while the Solomon arc has experienced very high levels of large-earthquake activity.

The importance of this tenth point is therefore not that a single simple plate boundary lies precisely at 158.84°E. Rather, the predicted 158.84°E ±3° belt coincides with an exceptionally active zone in which spreading, subduction, arc volcanism and microplate deformation interact. For this reason, 158.84°E should probably be retained as a candidate tenth equatorial node, even if its precise geological expression remains unresolved.

The larger pattern

The sequence is noteworthy because the theoretical coordinates are generated independently of the geological features:

111.16°W → 81.16°W → 51.16°W → 21.16°W → 8.84°E → 38.84°E → 68.84°E → 98.84°E → 128.84°E → 158.84°E.

Across these ten consecutive 30° positions one encounters, in order: East Pacific spreading → South American continental margin → Amazon/Atlantic continental margin → Mid-Atlantic spreading → African continental margin → East African rifting → Indian Ocean spreading → Sunda subduction → Molucca arc collision → Woodlark–Solomon spreading/subduction.

The geological processes are therefore not of one type. Some points correspond to spreading ridges, others to continental margins, rifts, subduction systems or complex collision zones. What they potentially have in common is their position relative to a regular deep-mantle framework.

This distinction is central to testing the model. The proposed lower-mantle divisions should not be expected to produce identical structures everywhere. The lithosphere above them differs greatly in age, thickness, composition and pre-existing tectonic architecture. The test is instead whether major changes in tectonic organization occur repeatedly within the predicted ±1.5° to ±3° belts around an independently defined 30° sequence.

The correspondence at 21.16°W, 68.84°E and approximately 111.16°W is particularly interesting because all three are associated with major oceanic spreading systems. The 38.84°E case provides a different and potentially important test: the lower-mantle division itself lies east of the Kenya Rift, while the predicted western influence line at 35.84°E approaches the actual rift axis closely. Eastern Indonesia at 128.84°E and the candidate point at 158.84°E show yet another manifestation, where the regular sequence enters some of the most structurally complicated convergent regions on Earth.

The Papua–Solomon point therefore deserves further investigation rather than premature classification. If 158.84°E ultimately proves to occupy a systematic position within the Woodlark–Solomon tectonic and magmatic system, it would extend an already remarkable 30° equatorial sequence by one further major tectonic node.

The 30° Equatorial Sequence and the ±3° Mantle-Roll Belts

Taking 21.16°W as a principal lower-mantle division, twelve equivalent divisions occur at exact 30° intervals around the equator. In the proposed convection-roll model, the surface expression does not necessarily coincide with the principal lower-mantle longitude. Upper-mantle upwelling occurs approximately 1.5° to either side, while geological effects of the adjacent roll may occur as far as 3° from the principal division.

The 30° Equatorial Sequence (yellow dots on the map)

No.	Principal division / belt	Main geological correspondence	Interpretation
1	111.16°W ±3°	East Pacific Rise	Major oceanic spreading system; ridge axis lies within the predicted mantle-roll belt.
2	81.16°W ±3°	Western margin of South America	Nazca–South America convergence and subduction along the Ecuador–Colombia margin.
3	51.16°W ±3°	Amazon mouth / NE South America	Major continental and sedimentary transition at the Atlantic margin; less directly tectonic than most other points.
4	21.16°W ±3°	Equatorial Mid-Atlantic Ridge	Major spreading system. The ridge/transform system approaches the eastern side of the predicted belt, near 18.16°W.
5	8.84°E ±3°	West coast of equatorial Africa	Atlantic continental margin and inherited structural zone of the Gabon Basin.
6	38.84°E ±3°	East African Rift	Kenya Rift lies toward the western side of the belt, close to the predicted 35.84°E outer influence line.
7	68.84°E ±3°	Central Indian Ridge	Major Indian Ocean spreading system; the ridge axis falls within the predicted belt.
8	98.84°E ±3°	Western Indonesia / Sunda margin	Major subduction system west of Sumatra, with strong seismic and volcanic activity.
9	128.84°E ±3°	Eastern Indonesia / Molucca–Halmahera	Exceptionally complex arc–arc collision, opposing subduction systems and intense magmatism.
10	158.84°E ±3°	Woodlark–Solomon region	Broad magmatic and tectonic zone involving spreading, subduction, microplates and the Solomon arc.
11	171.16°W ±3°	Phoenix / Nova–Canton region	Major old Pacific fracture-zone system; Nova–Canton Trough lies remarkably close to the 168.16°W outer line.
12	141.16°W ±3°	Central Pacific	Weakest equatorial case; no major active plate boundary directly at the principal longitude, although important fracture-zone and volcanic structures occur within the wider region.

What stands out

The most striking feature is that the sequence does not repeatedly select the same type of structure. Instead it encounters very different manifestations of lithospheric deformation:

spreading ridge → subduction margin → passive continental margin → spreading ridge → passive margin → continental rift → spreading ridge → subduction → arc collision → spreading/subduction complex → fracture zone → intraplate volcanic/fracture-zone province.

That heterogeneity may actually be important for the model. If the 30° divisions represent a deep mantle framework, one should not necessarily expect identical surface structures. Oceanic and continental lithosphere respond differently, and the existing plate geometry determines whether a mantle-related influence is expressed as spreading, faulting, rifting, volcanism or enhanced deformation at a pre-existing boundary.

Three cases are particularly clean geometrically:

21.16°W: the Romanche/Mid-Atlantic ridge region approaches the predicted +3° position at 18.16°W.

38.84°E: the Kenya Rift near 36.1°E approaches the predicted −3° position at 35.84°E.

171.16°W: Nova–Canton Trough near 168.01°W approaches the predicted +3° position at 168.16°W.

There is also an important distinction at 148°E, which is not one of the 30° lower-mantle divisions. As we discussed, that longitude belongs instead to the strong tectonic line produced by the overlapping tectonic-ring geometry. Independent studies find major tectonic changes around 147–149°E: east of ~148°E the Papuan plate boundary becomes increasingly extensional, while around 147–148°E earthquake slip-vector orientations and microplate relationships change markedly.

So we now have two different geometrical systems that should not be mixed:

The 30° sequence describes the proposed regular lower-mantle/convection-roll framework.

The ~29°E → ~91°W → ~148°E set arises from the geometry of the tectonic rings and appears to identify unusually strong zones of tectonic reorganisation.