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Hotspot (Geology)

The Earth, in its perpetually restless state, occasionally reveals pockets of activity that defy the elegant simplicity of plate tectonics. These are the volcanic locales known as hotspots, regions where the infernal heat of the planet's interior seems to punch through the crust, creating a sustained source of magma far from the conventional battlegrounds of plate boundaries. It's as if the mantle itself has a localized fever, manifesting as areas anomalously hot compared to its surroundings, a geological anomaly that has kept researchers scratching their heads for decades.

A prime example of such a phenomenon is depicted in the accompanying diagram, illustrating a cross section through our planet at the famous Hawaii hotspot. Here, magma, originating deep within the mantle, embarks on an arduous journey, ascending through the ductile asthenosphere and eventually breaching the rigid lithosphere. This relentless upwelling fuels a continuous chain of volcanoes, a testament to the inexorable movement of the lithospheric plate above a relatively stationary, persistent source of molten rock. The progression, often marked in millions of years (Ma), clearly charts the path of the plate as it glides over this subterranean furnace.

In the realm of geology, these enigmatic hotspots (or hot spots, if you prefer the slightly less committed spelling) are widely recognized as persistent sources of volcanism that are thought to be nourished by underlying mantle material exhibiting temperatures significantly higher than the ambient mantle around it. [1] Notable examples of these geological curiosities include the aforementioned Hawaii, the perpetually active Iceland, and the perpetually simmering Yellowstone hotspots. A hotspot's geographical footprint on the Earth's surface maintains a stubborn independence from the intricate dance of tectonic plate boundaries. This geological autonomy means that as the colossal tectonic plates drift ponderously across the Earth's face, they carry with them the crust above these stationary hot zones, consequently forging a distinctive, often linear, chain of volcanoes in their wake.

Hypotheses

The scientific community, ever eager to categorize and explain, has put forth two primary hypotheses in an attempt to unravel the mysteries of hotspot origins. One school of thought, the more dramatic of the two, posits that hotspots owe their existence to profound mantle plumes. These plumes are envisioned as colossal, buoyant columns of superheated rock that rise as thermal diapirs – essentially, slow-motion, superheated bubbles – from the deep recesses of the core–mantle boundary. [2] It's a grand, compelling narrative of deep Earth dynamics.

The alternative, often termed the plate theory, offers a less theatrical, yet equally plausible, explanation. This perspective suggests that the mantle source lying directly beneath a hotspot isn't necessarily anomalously hot at all. Instead, it proposes that the overlying crust is either unusually weak or remarkably thin. This inherent weakness or attenuation then facilitates lithospheric extension, allowing for the comparatively passive upwelling of molten material from shallower depths within the mantle. [3] [4] Both theories grapple with the same observable phenomena, offering fundamentally different insights into the Earth's complex internal plumbing.

Origin

The genesis of the hotspot concept, a notion that has profoundly shaped our understanding of intraplate volcanism, can be traced back to the groundbreaking work of J. Tuzo Wilson. In 1963, Wilson, with a flash of geological insight, postulated that the distinctive linear arrangement and age progression of the Hawaiian Islands could be elegantly explained by the slow, inexorable movement of the Pacific tectonic plate across a persistent, stationary hot region situated deep beneath the Earth's surface. [5]

Building upon Wilson's foundational idea, it was subsequently theorized that these hotspots are continuously fed by vast, ascending streams of hot mantle material. These streams, originating from the profound depths of the Earth's core–mantle boundary, coalesce into a distinct, column-like structure, aptly named a mantle plume. [6] However, the very existence of such mantle plumes, and their precise role in driving hotspot volcanism, has become the focal point of a significant and often contentious debate within the Earth science community. [4] [7] Despite the protracted arguments, recent advancements in seismic imaging have begun to yield observations that are remarkably consistent with the evolving theoretical models of these deep-seated plumes, offering a grudging truce in some aspects of the controversy. [8]

Any geological locale where volcanism manifests without an apparent connection to the more conventional constructive (divergent) or destructive (convergent) plate margins is typically attributed to the concept of a hotspot. A comprehensive review article by Courtillot et al. [9] meticulously cataloged potential hotspots, introducing a crucial distinction between "primary" and "secondary" types. Primary hotspots are envisioned as originating from the deepest reaches of the mantle, likely from the core–mantle boundary, and are responsible for generating expansive volcanic provinces that leave behind distinct linear tracks as the overlying plate moves. Confirmed examples include Easter Island, Iceland, Hawaii, Afar, Louisville, Reunion, and Tristan, with Galapagos, Kerguelen, and Marquesas also strong contenders. Secondary hotspots, in contrast, are thought to derive from shallower depths, specifically the upper/lower mantle boundary. These do not typically form vast volcanic provinces but rather create chains of islands, such as Samoa, Tahiti, Cook, Pitcairn, Caroline, and MacDonald, with potentially twenty or more additional possibilities. Other postulated hotspots are merely the superficial consequence of shallow mantle material being permitted to rise in areas where the lithosphere is actively undergoing break-up due to tensional forces, representing a fundamentally different style of volcanism entirely.

Estimates for the sheer number of hotspots believed to be fed by these deep mantle plumes have varied wildly, ranging from a conservative twenty to an enthusiastic several thousand. Most geologists, however, tend to converge on a more moderate figure, suggesting that perhaps a few dozen truly active hotspots exist at any given time. [8] Among the most intensely studied and volcanically active regions where this hypothesis is applied are Hawaii, Réunion, Yellowstone, Galápagos, and Iceland. Interestingly, the plumes that have been successfully imaged to date through sophisticated seismic techniques are far from the simple, relatively narrow, and purely thermal columns that many early models envisioned. They display considerable variability in width and other characteristics, often appearing tilted and complex, refusing to conform to neat theoretical diagrams. [8] To date, only one, the Yellowstone hotspot, has been consistently modeled and imaged across its entire hypothesized extent, from the deep mantle all the way to the Earth's surface, a true geological celebrity. [8]

Composition

When it comes to the raw material erupting from these geological hot zones, most hotspot volcanoes are predominantly basaltic in composition. This is evident in iconic examples like Hawaii and Tahiti. The inherent nature of basaltic magma, which is generally fluid and relatively low in volatile content, means that these eruptions tend to be considerably less explosive than those observed at subduction zone volcanoes. In subduction zones, the process of one plate diving beneath another traps vast quantities of water beneath the overriding plate, and this water, when heated, can lead to highly violent, steam-driven eruptions.

However, the narrative shifts dramatically when hotspots manifest in continental regions. In these scenarios, the ascending basaltic magma, with its intense heat, encounters and begins to melt the much thicker, more silicic continental crust. This process of crustal melting generates a different, more viscous type of magma: rhyolite. And rhyolites, laden with trapped gases and possessing a higher viscosity, are notorious for producing exceptionally violent and explosive eruptions. [10] [11]

A stark illustration of this destructive potential is the Yellowstone Caldera, which was sculpted by some of the most cataclysmic volcanic explosions in the entirety of geologic history. These were not mere eruptions; they were geological events of staggering scale. Yet, even after such a colossal discharge of rhyolitic material, the underlying dynamics can persist. Once the bulk of the rhyolite has been violently expelled, the system may revert to its more fundamental basaltic character, with subsequent eruptions delivering basaltic magma through the very same lithospheric fissures (cracks in the lithosphere) that once channeled the explosive rhyolite. An excellent example of this sequential activity is found in the Ilgachuz Range in British Columbia, where an initial, complex series of trachyte and rhyolite eruptions eventually gave way to the later extrusion of more placid basaltic lava flows. [12]

The understanding of hotspot composition, particularly the geochemical signatures embedded within the erupted rocks, is now inextricably linked to the broader mantle plume hypothesis. [13] [8] The advent of sophisticated analytical techniques has enabled detailed compositional studies of hotspot basalts, allowing geologists to establish connections between samples collected over vast geographical areas. These studies provide crucial evidence that often implicates the deeper, more expansive plume hypothesis, further reinforced by advances in seismic imaging that visually map these subterranean structures. [8]

Contrast with subduction zone island arcs

It's crucial to understand that hotspot volcanoes, despite their often impressive stature, are considered to originate from a fundamentally different set of geological processes than their counterparts, island arc volcanoes. The latter form within the dynamic, often violent, arenas of subduction zones, which are areas where tectonic plates converge. In this grand collision, when one oceanic plate, typically denser, encounters another, it is inexorably forced to descend beneath it, plunging into a deep ocean trench.

As this subducting plate plunges deeper into the Earth's mantle, it carries with it significant amounts of water, which is bound within its mineral structure. At certain depths, as temperatures and pressures increase, this water is released into the base of the overriding plate. This liberated water acts as a flux, lowering the melting point of the surrounding mantle rock and altering its chemical composition, which in turn causes some of the rock to melt and ascend. This rising molten material is the very fuel that powers a chain of volcanoes, creating characteristic island arcs such as the dramatic Aleutian Islands located off the coast of Alaska. Hotspots, by contrast, are insulated from these plate-boundary interactions, drawing their fiery sustenance from deeper, more isolated sources within the mantle.

Hotspot volcanic chains

The combined mantle plume and hotspot hypothesis, in its original, elegant formulation, envisioned the deep feeder structures as being relatively fixed in their positions, while the colossal continents and seafloor drifted majestically overhead. This theoretical framework, therefore, made a clear and compelling prediction: that the movement of the overlying tectonic plate would result in the development of time-progressive chains of volcanoes on the Earth's surface. Each volcano in the chain would be a chronological marker, older ones trailing behind, younger ones forming over the active hotspot.

Consider the Yellowstone hotspot, for instance, which sits at the southeastern end of a remarkable chain of extinct calderas. These ancient volcanic depressions, with an almost uncanny geological precision, become progressively older as one traces the chain westward, clearly illustrating the path of the North American plate over the stationary plume. Another classic example is the magnificent Hawaiian archipelago and its submerged extension, the Emperor Seamounts. Here, the islands themselves, and the vast underwater mountains that precede them, become progressively older and more deeply eroded as one moves towards the northwest, a geological timeline etched into the very fabric of the Pacific plate. The active volcanoes of Kilauea and Mauna Loa represent the current manifestations of this process, with Kilauea being renowned as the most active shield volcano globally, erupting almost continuously from 1983 to 2018, and Mauna Loa having its last eruption in 2022. Towering above them all, Mauna Kea stands as the tallest volcano in the Hawaiian–Emperor seamount chain, its summit adorned with numerous cinder cones. Further north, other examples include the Bowie Seamount, a dormant submarine volcano forming part of the Kodiak-Bowie Seamount chain, and Axial Seamount, the youngest member of the Cobb–Eickelberg Seamount chain, which last erupted in 2015. Even Hualalai, a massive shield volcano within the Hawaiian–Emperor seamount chain, had its last eruption in 1801, long before many modern observations.

However, the relentless scrutiny of geologists has revealed that this seemingly straightforward model of plate tracking isn't without its complications. The effort to precisely map the movement of the Earth's tectonic plates using these volcanic chains has been, shall we say, "vexed." This vexation stems from several inconvenient truths: the scarcity of truly long, uninterrupted chains; the observation that many chains, such as those found in the Galápagos Islands, are decidedly not time-progressive in their age distribution; and perhaps most critically, the growing realization that hotspots themselves do not appear to be perfectly fixed relative to one another (a point starkly illustrated by the relative movement observed between the Hawaii and Iceland hotspots). [15] The current, more nuanced understanding now acknowledges that mantle plumes are far more complex and dynamic than initially hypothesized, exhibiting independent movements relative to each other and to the overlying plates, a complexity that, frankly, makes perfect sense for a planet that refuses to be simple. [8]

In a rather impressive feat of geological detective work, Wei et al. in 2020 utilized advanced seismic tomography to detect the ancient oceanic plateau that was originally formed approximately 100 million years ago by the hypothesized mantle plume head of the Hawaii-Emperor seamount chain. This colossal geological feature, a relic of primordial volcanism, has since been subducted to an astonishing depth of 800 kilometers beneath the vast expanse of eastern Siberia, a testament to the Earth's ability to recycle its own crust over immense timescales. [16]

Postulated hotspot volcano chains

For those who appreciate the linear elegance of geological processes, here are some of the most prominent postulated hotspot volcano chains, each a testament to the slow, persistent burn of a deep mantle anomaly and the inexorable drift of a tectonic plate across it. Each chain represents a geological narrative, a trail of fire and rock left behind over millions of years, as neatly summarized by one recent group. [9] (Figure from Foulger (2010)). [4]

List of volcanic regions postulated to be hotspots

This exhaustive compendium details various volcanic regions that have been postulated to be active hotspots, meticulously categorized by their associated tectonic plates. For each entry, "az" denotes the azimuth of the hotspot track, indicating its direction of movement, while "w" represents the "weight," or the estimated accuracy of that azimuth, with 1 being the most accurate and 0.2 the least. [19] Because even geological certainty is a spectrum.

Map all coordinates using OpenStreetMap Download coordinates as KML

Eurasian plate

  • Eifel hotspot (8)
    • 50°12′N 6°42′E / 50.2°N 6.7°E / 50.2; 6.7 (Eifel hotspot), w= 1 az= 082° ±8° rate= 12 ±2 mm/yr [19]
  • Iceland hotspot (14)
    • 64°24′N 17°18′W / 64.4°N 17.3°W / 64.4; -17.3 (Iceland hotspot) [19]
    • Eurasian Plate, w= 0.8 az= 075° ±10° rate= 5 ±3 mm/yr
    • North American Plate, w= 0.8 az= 287° ±10° rate= 15 ±5 mm/yr
    • Possibly a relic or ongoing contributor to the North Atlantic continental rifting that commenced around 62 million years ago and affected Greenland. [20]
  • Azores hotspot (1)
    • 37°54′N 26°00′W / 37.9°N 26.0°W / 37.9; -26.0 (Azores hotspot) [19]
    • Eurasian Plate, w= 0.5 az= 110° ±12°
    • North American Plate, w= 0.3 az= 280° ±15°
  • Jan Mayen hotspot (15)
    • 71°00′N 9°00′W / 71.0°N 9.0°W / 71.0; -9.0 (Jan Mayen hotspot) [19]
  • Hainan hotspot (46)
    • 20°00′N 110°00′E / 20.0°N 110.0°E / 20.0; 110.0 (Hainan hotspot), az= 000° ±15° [19]

African plate

  • Mount Etna (47)
    • 37°45′N 15°00′E / 37.750°N 15.000°E / 37.750; 15.000 (Mount Etna) [19]
  • Hoggar hotspot (13)
    • 23°18′N 5°36′E / 23.3°N 5.6°E / 23.3; 5.6 (Hoggar hotspot), w= 0.3 az= 046° ±12° [19]
  • Tibesti hotspot (40)
    • 20°48′N 17°30′E / 20.8°N 17.5°E / 20.8; 17.5 (Tibesti hotspot), w= 0.2 az= 030° ±15° [19]
  • Jebel Marra/Darfur hotspot (6)
    • 13°00′N 24°12′E / 13.0°N 24.2°E / 13.0; 24.2 (Darfur hotspot), w= 0.5 az= 045° ±8° [19]
  • Afar hotspot (29, misplaced in map)
    • 7°00′N 39°30′E / 7.0°N 39.5°E / 7.0; 39.5 (Afar hotspot), w= 0.2 az= 030° ±15° rate= 16 ±8 mm/yr [19]
    • Possibly intrinsically linked to the complex Afar triple junction, a point where three tectonic plates meet, active for approximately 30 million years.
  • Cameroon hotspot (17)
    • 2°00′N 5°06′E / 2.0°N 5.1°E / 2.0; 5.1 (Cameroon hotspot), w= 0.3 az= 032° ±3° rate= 15 ±5 mm/yr [19]
  • Madeira hotspot (48)
    • 32°36′N 17°18′W / 32.6°N 17.3°W / 32.6; -17.3 (Madeira hotspot), w= 0.3 az= 055° ±15° rate= 8 ±3 mm/yr [19]
  • Canary hotspot (18)
    • 28°12′N 18°00′W / 28.2°N 18.0°W / 28.2; -18.0 (Canary hotspot), w= 1 az= 094° ±8° rate= 20 ±4 mm/yr [19]
  • New England/Great Meteor hotspot (28)
    • 29°24′N 29°12′W / 29.4°N 29.2°W / 29.4; -29.2 (Great Meteor hotspot), w= 0.8 az= 040° ±10° [19]
  • Cape Verde hotspot (19)
    • 16°00′N 24°00′W / 16.0°N 24.0°W / 16.0; -24.0 (Cape Verde hotspot), w= 0.2 az= 060° ±30° [19]
  • Sierra Leone hotspot
  • St. Helena hotspot (34)
    • 16°30′S 9°30′W / -16.5°S 9.5°W / -16.5; -9.5 (St. Helena hotspot), w= 1 az= 078° ±5° rate= 20 ±3 mm/yr [19]
  • Gough hotspot (49), situated at 40°19' S 9°56' W. [21] [22]
    • 40°18′S 10°00′W / -40.3°S 10.0°W / -40.3; -10.0 (Gough hotspot), w= 0.8 az= 079° ±5° rate= 18 ±3 mm/yr [19]
  • Tristan hotspot (42), located at 37°07′ S 12°17′ W.
    • 37°12′S 12°18′W / -37.2°S 12.3°W / -37.2; -12.3 (Tristan hotspot) [19]
  • Vema hotspot (associated with Vema Seamount, 43), found at 31°38' S 8°20' E.
    • 32°06′S 6°18′W / -32.1°S 6.3°W / -32.1; -6.3 (Vema hotspot) [19]
    • Potentially related to the massive Paraná and Etendeka traps, a large igneous province that erupted approximately 132 million years ago, with its activity potentially channeled through the structural feature known as the Walvis Ridge.
  • Discovery hotspot (50) (associated with the Discovery Seamounts)
    • 43°00′S 2°42′W / -43.0°S 2.7°W / -43.0; -2.7 (Discovery hotspot), w= 1 az= 068° ±3° [19]
  • Bouvet hotspot (51)
    • 54°24′S 3°24′E / -54.4°S 3.4°E / -54.4; 3.4 (Bouvet hotspot) [19]
  • Shona/Meteor hotspot (27)
    • 51°24′S 1°00′W / -51.4°S 1.0°W / -51.4; -1.0 (Shona hotspot), w= 0.3 az= 074° ±6° [19]
  • Réunion hotspot (33)
    • 21°12′S 55°42′E / -21.2°S 55.7°E / -21.2; 55.7 (Réunion hotspot), w= 0.8 az= 047° ±10° rate= 40 ±10 mm/yr [19]
    • Possibly linked to the immense Deccan Traps in India, a colossal large igneous province with its main eruptive events occurring between 68.5 and 66 million years ago.
  • Comoros hotspot (21)
    • 11°30′S 43°18′E / -11.5°S 43.3°E / -11.5; 43.3 (Comoros hotspot), w= 0.5 az=118 ±10° rate=35 ±10 mm/yr [19]

Antarctic plate

  • Marion hotspot (25)
    • 46°54′S 37°36′E / -46.9°S 37.6°E / -46.9; 37.6 (Marion hotspot), w= 0.5 az= 080° ±12° [19]
  • Crozet hotspot (52)
    • 46°06′S 50°12′E / -46.1°S 50.2°E / -46.1; 50.2 (Crozet hotspot), w= 0.8 az= 109° ±10° rate= 25 ±13 mm/yr [19]
    • Possibly related to the Karoo-Ferrar geologic province, another significant large igneous province, which formed approximately 183 million years ago.
  • Kerguelen hotspot (20)
    • 49°36′S 69°00′E / -49.6°S 69.0°E / -49.6; 69.0 (Kerguelen hotspot), w= 0.2 az= 050° ±30° rate= 3 ±1 mm/yr [19]
    • Intimately related to the vast Kerguelen Plateau, a large oceanic plateau that formed around 130 million years ago.
  • Heard hotspot (53), potentially an extension or part of the larger Kerguelen hotspot system. [14]
    • 53°06′S 73°30′E / -53.1°S 73.5°E / -53.1; 73.5 (Heard hotspot), w= 0.2 az= 030° ±20° [19]
    • The islands of Île Saint-Paul and Île Amsterdam could also be considered components of the extensive Kerguelen hotspot trail, though St. Paul is possibly not a distinct hotspot in itself. [14]
  • Balleny hotspot (2)
    • 67°36′S 164°48′E / -67.6°S 164.8°E / -67.6; 164.8 (Balleny hotspot), w= 0.2 az= 325° ±7° [19]
  • Erebus hotspot (54)
    • 77°30′S 167°12′E / -77.5°S 167.2°E / -77.5; 167.2 (Erebus hotspot) [19]

South American plate

  • Trindade/Martin Vaz hotspot (41)
    • 20°30′S 28°48′W / -20.5°S 28.8°W / -20.5; -28.8 (Trindade hotspot), w= 1 az= 264° ±5° [19]
  • Fernando hotspot (9)
    • 3°48′S 32°24′W / -3.8°S 32.4°W / -3.8; -32.4 (Fernando hotspot), w= 1 az= 266° ±7° [19]
    • Possibly connected to the colossal Central Atlantic Magmatic Province (CAMP), whose main eruptive events occurred around 200 million years ago, marking a pivotal moment in Earth's geological history.
  • Ascension hotspot (55)
    • 7°54′S 14°18′W / -7.9°S 14.3°W / -7.9; -14.3 (Ascension hotspot) [19]

North American plate

  • Bermuda hotspot (56)
    • 32°36′N 64°18′W / 32.6°N 64.3°W / 32.6; -64.3 (Bermuda hotspot), w= 0.3 az= 260° ±15° [19]
  • Yellowstone hotspot (44)
    • 44°30′N 110°24′W / 44.5°N 110.4°W / 44.5; -110.4 (Yellowstone hotspot), w= 0.8 az= 235° ±5° rate= 26 ±5 mm/yr [19]
    • Potentially related to the massive Columbia River Basalt Group, a flood basalt province that erupted between 17 and 14 million years ago, indicating a shared deep mantle source or a linked series of events. [23]
  • Raton hotspot (32)
    • 36°48′N 104°06′W / 36.8°N 104.1°W / 36.8; -104.1 (Raton hotspot), w= 1 az= 240°±4° rate= 30 ±20 mm/yr [19]
  • Anahim hotspot (45)
    • 52°54′N 123°44′W / 52.900°N 123.733°W / 52.900; -123.733 (Anahim hotspot) (associated with the Nazko Cone) [24]

Australian plate

  • Lord Howe hotspot (22)
    • 34°42′S 159°48′E / -34.7°S 159.8°E / -34.7; 159.8 (Lord Howe hotspot), w= 0.8 az= 351° ±10° [19]
  • Tasmantid hotspot (39)
    • 40°24′S 155°30′E / -40.4°S 155.5°E / -40.4; 155.5 (Tasmanid hotspot), w= 0.8 az= 007° ±5° rate= 63 ±5 mm/yr [19]
  • East Australia hotspot (30)
    • 40°48′S 146°00′E / -40.8°S 146.0°E / -40.8; 146.0 (East Australia hotspot), w= 0.3 az= 000° ±15° rate= 65 ±3 mm/yr [19]

Nazca plate

  • Juan Fernández hotspot (16)
    • 33°54′S 81°48′W / -33.9°S 81.8°W / -33.9; -81.8 (Juan Fernández hotspot), w= 1 az= 084° ±3° rate= 80 ±20 mm/yr [19]
  • San Felix hotspot (36)
    • 26°24′S 80°06′W / -26.4°S 80.1°W / -26.4; -80.1 (San Felix hotspot), w= 0.3 az= 083° ±8° [19]
  • Easter hotspot (7)
    • 26°24′S 106°30′W / -26.4°S 106.5°W / -26.4; -106.5 (Easter hotspot), w= 1 az= 087° ±3° rate= 95 ±5 mm/yr [19]
  • Galápagos hotspot (10)
    • 0°24′S 91°36′W / -0.4°S 91.6°W / -0.4; -91.6 (Galápagos hotspot) [19]
    • Nazca Plate, w= 1 az= 096° ±5° rate= 55 ±8 mm/yr
    • Cocos Plate, w= 0.5 az= 045° ±6°
    • Possibly related to the expansive Caribbean large igneous province (CLIP), whose main eruptive events occurred between 95 and 88 million years ago, suggesting a shared deep mantle source or a dynamic interaction.

Pacific plate

The vast Pacific plate, in its millions of years of relentless motion, has traversed numerous hotspots, leaving behind a remarkable geological signature. For instance, its journey over the Bowie hotspot has meticulously sculpted the Kodiak–Bowie Seamount chain across the expansive Gulf of Alaska, a trail of submerged mountains documenting its ancient path. This region is part of what some geologists refer to as the "Hotspot highway" in the south Pacific Ocean, a testament to the sheer number and activity of these deep-seated mantle anomalies.

  • Louisville hotspot (23)
    • 53°36′S 140°36′W / -53.6°S 140.6°W / -53.6; -140.6 (Louisville hotspot), w= 1 az= 316° ±5° rate= 67 ±5 mm/yr [19]
    • Possibly related to the colossal Ontong Java Plateau, one of the largest oceanic plateaus on Earth, which formed between 125 and 120 million years ago.
  • Foundation hotspot/Ngatemato seamounts (57)
    • 37°42′S 111°06′W / -37.7°S 111.1°W / -37.7; -111.1 (Foundation hotspot), w= 1 az= 292° ±3° rate= 80 ±6 mm/yr [19]
  • Macdonald hotspot (24)
    • 29°00′S 140°18′W / -29.0°S 140.3°W / -29.0; -140.3 (Macdonald hotspot), w= 1 az= 289° ±6° rate= 105 ±10 mm/yr [19]
  • North Austral/President Thiers (associated with President Thiers Bank, 58)
    • 25°36′S 143°18′W / -25.6°S 143.3°W / -25.6; -143.3 (North Austral hotspot), w= (1.0) az= 293° ± 3° rate= 75 ±15 mm/yr [19]
  • Arago hotspot (associated with Arago Seamount, 59)
    • 23°24′S 150°42′W / -23.4°S 150.7°W / -23.4; -150.7 (Arago hotspot), w= 1 az= 296° ±4° rate= 120 ±20 mm/yr [19]
  • Maria/Southern Cook hotspot (associated with Îles Maria, 60)
    • 20°12′S 153°48′W / -20.2°S 153.8°W / -20.2; -153.8 (Maria/Southern Cook hotspot), w= 0.8 az= 300° ±4° [19]
  • Samoa hotspot (35)
    • 14°30′S 168°12′W / -14.5°S 168.2°W / -14.5; -168.2 (Samoa hotspot), w= 0.8 az= 285°±5° rate= 95 ±20 mm/yr [19]
  • Crough hotspot (associated with Crough Seamount, 61)
    • 26°54′S 114°36′W / -26.9°S 114.6°W / -26.9; -114.6 (Crough hotspot), w= 0.8 az= 284° ± 2° [19]
  • Pitcairn hotspot (31)
    • 25°24′S 129°18′W / -25.4°S 129.3°W / -25.4; -129.3 (Pitcairn hotspot), w= 1 az= 293° ±3° rate= 90 ±15 mm/yr [19]
  • Society/Tahiti hotspot (38)
    • 18°12′S 148°24′W / -18.2°S 148.4°W / -18.2; -148.4 (Society hotspot), w= 0.8 az= 295°±5° rate= 109 ±10 mm/yr [19]
  • Marquesas hotspot (26)
    • 10°30′S 139°00′W / -10.5°S 139.0°W / -10.5; -139.0 (Marquesas hotspot), w= 0.5 az= 319° ±8° rate= 93 ±7 mm/yr [19]
  • Caroline hotspot (4)
    • 4°48′N 164°24′E / 4.8°N 164.4°E / 4.8; 164.4 (Caroline hotspot), w= 1 az= 289° ±4° rate= 135 ±20 mm/yr [19]
  • Hawaii hotspot (12)
    • 19°00′N 155°12′W / 19.0°N 155.2°W / 19.0; -155.2 (Hawaii hotspot), w= 1 az= 304° ±3° rate= 92 ±3 mm/yr [19]
  • Socorro/Revillagigedos hotspot (37)
    • 19°00′N 111°00′W / 19.0°N 111.0°W / 19.0; -111.0 (Socorro) [19]
  • Guadalupe hotspot (11)
    • 27°42′N 114°30′W / 27.7°N 114.5°W / 27.7; -114.5 (Guadalupe hotspot), w= 0.8 az= 292° ±5° rate= 80 ±10 mm/yr [19]
  • Cobb hotspot (5)
    • 46°00′N 130°06′W / 46.0°N 130.1°W / 46.0; -130.1 (Cobb hotspot), w= 1 az= 321° ±5° rate= 43 ±3 mm/yr [19]
  • Bowie/Pratt-Welker hotspot (3)
    • 53°00′N 134°48′W / 53.0°N 134.8°W / 53.0; -134.8 (Bowie hotspot), w= 0.8 az= 306° ±4° rate= 40 ±20 mm/yr [19]

Former hotspots

Even geological anomalies, like all things, eventually fade or are overwritten by the relentless march of plate tectonics. Here are a few hotspots that are no longer considered active, having left their indelible mark on the Earth's crust before ceasing their fiery output.

See also