Susan Ellis (geophysicist)

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Susan Marian Ellis (born 1965) is a geophysicist based in New Zealand, who specialises in modelling the geodynamics of the Earth's crust deformation, at different scales. [1] Ellis is a principal scientist at GNS Science [2] and her main interests are in subduction, seismology, tectonics, crust and petrology. [3] Ellis's current work focuses on the influence of faulting on stresses in the crust, and how this is related to geological hazard and the tectonic settings in New Zealand. [1]

Contents

Education

Born in 1965, [4] Ellis earned a Bachelor of Science degree with honours at Victoria University of Wellington. [1] She subsequently completed her PhD in 1995 at Dalhousie University, where she examined the forces driving continental collision using numerical models, applied to Tibet and New Zealand. [4] This was followed by postdoctoral fellowships at Dalhousie University (1996–1997), as part of the Lithoprobe programme, [5] [6] and the University of Berne, studying the geodynamics of the Swiss Alps.

Career and impact

Ellis has worked with and developed 2D and 3D numerical methods incorporating faults, inelastic rheology of the crust and mantle, and thermal and fluid evolution. [7] She has investigated studies of rifting exhumation mechanics in Papua New Guinea; mechanics of the Wilson cycle; fluid and magma generation and flow in the Taupō Volcanic Zone; subduction initiation; and subduction dynamics. [8] [9] [10] Her work has focused on the influence of faulting on stresses in the crust, and the interplay between seismic and interseismic deformation, as applied to New Zealand tectonic settings.

Awards and honours

In 2005, Ellis was elected president of the New Zealand Geophysics Society (which has since merged to become the New Zealand Geoscience Society). [1] In 2020, she was awarded the Geological Society of New Zealand's "New Zealand McKay Hammer Award" for the most outstanding published research on New Zealand geology in the preceding three years. [11] The citation reads "For a body of work as a leading geodynamic modeller, making pivotal contributions to our understanding of tectonics".

In 2021, Ellis was a co-winner (along with first author Donna Eberhart Phillips) of the Geological Society of New Zealand's "New Zealand Geophysics Prize", the society's top geophysical award bestowed upon the author or authors of the most meritorious recent publication in the field of geophysics. [12]

Selected work

Related Research Articles

<span class="mw-page-title-main">Subduction</span> A geological process at convergent tectonic plate boundaries where one plate moves under the other

Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with rates of convergence as high as 11 cm/year.

<span class="mw-page-title-main">Tonga Trench</span> Deepest oceanic trench in the southwestern Pacific Ocean

The Tonga Trench is an oceanic trench located in the southwestern Pacific Ocean. It is the deepest trench in the Southern hemisphere and the second deepest on Earth after the Mariana Trench. The fastest plate-tectonic velocity on Earth is occurring at this location, as the Pacific Plate is being subducted westward in the trench.

<span class="mw-page-title-main">Australian Plate</span> Major tectonic plate separated from Indo-Australian Plate about 3 million years ago

The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately 100 million years ago when India broke away and began moving north. Australia and Antarctica had begun rifting by 96 million years ago and completely separated a while after this, some believing as recently as 45 million years ago, but most accepting presently that this had occurred by 60 million years ago.

An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. Earthquakes of this type account for more than 90 percent of the total seismic energy released around the world. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other. The slipping process creates an earthquake with relative displacement on either side of the fault, resulting in seismic waves which travel through the Earth and along the Earth's surface. Relative plate motion can be lateral as along a transform fault boundary, vertical if along a convergent boundary or a divergent boundary, and oblique, with horizontal and lateral components at the boundary. Interplate earthquakes associated at a subduction boundary are called megathrust earthquakes, which include most of the Earth's largest earthquakes.

<span class="mw-page-title-main">Aseismic creep</span> Surface displacement along a geological fault without earthquakes occurring

In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "after-slip" days to years after an earthquake. Notable examples of aseismic slip include faults in California.

A slow earthquake is a discontinuous, earthquake-like event that releases energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake. First detected using long term strain measurements, most slow earthquakes now appear to be accompanied by fluid flow and related tremor, which can be detected and approximately located using seismometer data filtered appropriately. That is, they are quiet compared to a regular earthquake, but not "silent" as described in the past.

Episodic tremor and slip (ETS) is a seismological phenomenon observed in some subduction zones that is characterized by non-earthquake seismic rumbling, or tremor, and slow slip along the plate interface. Slow slip events are distinguished from earthquakes by their propagation speed and focus. In slow slip events, there is an apparent reversal of crustal motion, although the fault motion remains consistent with the direction of subduction. ETS events themselves are imperceptible to human beings and do not cause damage.

<span class="mw-page-title-main">Hikurangi Plateau</span> A large igneous province and subsurface plateau in the Pacific Ocean

The Hikurangi Plateau is an oceanic plateau in the South Pacific Ocean east of the North Island of New Zealand. It is part of a large igneous province (LIP) together with Manihiki and Ontong Java, now located 3,000 km (1,900 mi) and 3,500 km (2,200 mi) north of Hikurangi respectively. Mount Hikurangi, in Māori mythology the first part of the North Island to emerge from the ocean, gave its name to the plateau.

<span class="mw-page-title-main">Nankai Trough</span> Trough off the coast of Japan

The Nankai Trough is a submarine trough located south of the Nankaidō region of Japan's island of Honshu, extending approximately 900 km (559 mi) offshore. The underlying fault, the Nankai megathrust, is the source of the devastating Nankai megathrust earthquakes, while the trough itself is potentially a major source of hydrocarbon fuel, in the form of methane clathrate.

Susan Y. Schwartz is a scientist at the University of California, Santa Cruz known for her research on earthquakes, through field projects conducted in locations in Costa Rica and the San Andreas Fault.

<span class="mw-page-title-main">Hikurangi Margin</span> Subduction zone off the east coast of New Zealands North Island

The Hikurangi Margin is New Zealand's largest subduction zone and fault.

<span class="mw-page-title-main">Flat slab subduction</span> Subduction characterized by a low subduction angle

Flat slab subduction is characterized by a low subduction angle beyond the seismogenic layer and a resumption of normal subduction far from the trench. A slab refers to the subducting lower plate. A broader definition of flat slab subduction includes any shallowly dipping lower plate, as in western Mexico. Flat slab subduction is associated with the pinching out of the asthenosphere, an inland migration of arc magmatism, and an eventual cessation of arc magmatism. The coupling of the flat slab to the upper plate is thought to change the style of deformation occurring on the upper plate's surface and form basement-cored uplifts like the Rocky Mountains. The flat slab also may hydrate the lower continental lithosphere and be involved in the formation of economically important ore deposits. During the subduction, a flat slab itself may deform or buckle, causing sedimentary hiatus in marine sediments on the slab. The failure of a flat slab is associated with ignimbritic volcanism and the reverse migration of arc volcanism. Multiple working hypotheses about the cause of flat slabs are subduction of thick, buoyant oceanic crust (15–20 km) and trench rollback accompanying a rapidly overriding upper plate and enhanced trench suction. The west coast of South America has two of the largest flat slab subduction zones. Flat slab subduction is occurring at 10% of subduction zones.

Alik Ismail-Zadeh is a mathematical geophysicist known for his contribution to computational geodynamics and natural hazard studies, pioneering work on data assimilation in geodynamics as well as for outstanding service to the Earth and space science community. He is Senior Research Fellow at the Karlsruhe Institute of Technology in Germany.

<span class="mw-page-title-main">Laura Wallace</span> American geophysicist

Laura Martin Wallace is a geodetic principal scientist who works between the University of Texas at Austin and GNS Science in New Zealand. She was elected Fellow of the Royal Society Te Apārangi in 2018.

Anne Sheehan is a geologist known for her research using seismometer data to examine changes in the Earth's crust and mantle.

Donna Eberhart-Phillips is a geologist known for her research on subduction zones, especially in Alaska and New Zealand.

<span class="mw-page-title-main">Oblique subduction</span> Tectonic process

Oblique subduction is a form of subduction for which the convergence direction differs from 90° to the plate boundary. Most convergent boundaries involve oblique subduction, particularly in the Ring of Fire including the Ryukyu, Aleutian, Central America and Chile subduction zones. In general, the obliquity angle is between 15° and 30°. Subduction zones with high obliquity angles include Sunda trench and Ryukyu arc.

<span class="mw-page-title-main">Earthquake cycle</span> Natural phenomenon

The earthquake cycle refers to the phenomenon that earthquakes repeatedly occur on the same fault as the result of continual stress accumulation and periodic stress release. Earthquake cycles can occur on a variety of faults including subduction zones and continental faults. Depending on the size of the earthquake, an earthquake cycle can last decades, centuries, or longer. The Parkfield portion of the San Andreas fault is a well-known example where similarly located M6.0 earthquakes have been instrumentally recorded every 30–40 years.

Demian (Michael) Saffer is an American geophysicist based at The University of Texas at Austin where he is director of the University of Texas Institute for Geophysics and professor at the Department of Geological Sciences of the Jackson School of Geosciences. He studies the role of fluids and friction in the mechanics of subduction megathrust earthquakes.

<span class="mw-page-title-main">Wishbone scarp</span> An ocean floor tectonic feature of the Pacific Ocean

The Wishbone scarp is a Pacific Ocean floor feature in the oceanic crust, that if it were on land would be similar to a mountain range fault system over 1,000 km (620 mi) long. It commences in the north near the Osbourn Trough although it is likely to be related tectonically to the Manihiki scarp somewhat to its north. To the south it splits into west and east scarps that have been intercepted by the Louisville hotspot with the West Wishbone scarp continuing until it intercepts the Chatham Rise. There is now evidence that the entire scarp has a fracture zone origin resolving previous uncertainty on this issue.

References

  1. 1 2 3 4 "Dr Susan Ellis". GNS Science | Te Pῡ Ao. Retrieved 5 October 2022.
  2. ↑ "Susan Ellis". GNS Science | Te Pῡ Ao. Retrieved 5 October 2022.
  3. ↑ "Susan Ellis: H-index & Awards - Academic Profile". Research.com. Retrieved 5 October 2022.
  4. 1 2 Ellis, Susan (1 September 2022). "Continental convergence :length-scales, aspect ratios, and styles of crustal deformation". Canada Libraries and Archives. Retrieved 5 October 2022.
  5. ↑ "Lithoprobe research project". Lithoprobe Research Project. Retrieved 5 October 2022.
  6. ↑ Ellis, Susan; Beaumont, Christopher (1 October 1999). "Models of convergent boundary tectonics: implications for the interpretation of Lithoprobe data". Canadian Journal of Earth Sciences (in French). 36 (10): 1711–1741. Bibcode:1999CaJES..36.1711E. doi:10.1139/e99-075. ISSN   0008-4077.
  7. ↑ "SULEC geodynamic finite-element code". SULEC geodynamic finite-element code (GNZ Science). Retrieved 5 October 2022.
  8. ↑ "Slow-motion earthquakes". New Zealand Geographic. Retrieved 5 October 2022.
  9. ↑ Austin, University of Texas at. "Sinking sea mountains make and muffle earthquakes". phys.org. Retrieved 5 October 2022.
  10. ↑ "Susan Ellis | East Coast LAB | Hikurangi Subduction Zone M9". www.eastcoastlab.org.nz. Retrieved 5 October 2022.
  11. ↑ "McKay Hammer Award » Geoscience Society of New Zealand". Geoscience Society of New Zealand. Retrieved 5 October 2022.
  12. ↑ Eberhart-Phillips, Donna; Ellis, Susan; Lanza, Federica; Bannister, Stephen (19 July 2021). "Heterogeneous material properties—as inferred from seismic attenuation—influenced multiple fault rupture and ductile creep of the Kaikoura Mw 7.8 earthquake, New Zealand". Geophysical Journal International. 227 (2): 1204–1227. doi: 10.1093/gji/ggab272 . ISSN   0956-540X.
  13. ↑ Sun, Tianhaozhe; Saffer, Demian; Ellis, Susan (March 2020). "Mechanical and hydrological effects of seamount subduction on megathrust stress and slip". Nature Geoscience. 13 (3): 249–255. Bibcode:2020NatGe..13..249S. doi:10.1038/s41561-020-0542-0. ISSN   1752-0908. S2CID   211729942.
  14. ↑ Webber, Sam; Ellis, Susan; Fagereng, Åke (April 2018). ""Virtual shear box" experiments of stress and slip cycling within a subduction interface mélange". Earth and Planetary Science Letters. 488: 27–35. Bibcode:2018E&PSL.488...27W. doi:10.1016/j.epsl.2018.01.035.
  15. ↑ Ellis, Susan; Fagereng, Åke; Barker, Dan; Henrys, Stuart; Saffer, Demian; Wallace, Laura; Williams, Charles; Harris, Rob (1 July 2015). "Fluid budgets along the northern Hikurangi subduction margin, New Zealand: the effect of a subducting seamount on fluid pressure". Geophysical Journal International. 202 (1): 277–297. doi: 10.1093/gji/ggv127 . ISSN   1365-246X.
  16. ↑ Ellis, S.M.; Little, T.A.; Wallace, L.M.; Hacker, B.R.; Buiter, S.J.H. (November 2011). "Feedback between rifting and diapirism can exhume ultrahigh-pressure rocks". Earth and Planetary Science Letters. 311 (3–4): 427–438. Bibcode:2011E&PSL.311..427E. doi:10.1016/j.epsl.2011.09.031.
  17. ↑ Ellis, S.M.; Wilson, C.J.N.; Bannister, S.; Bibby, H.M.; Heise, W.; Wallace, L.; Patterson, N. (November 2007). "A future magma inflation event under the rhyolitic Taupo volcano, New Zealand: Numerical models based on constraints from geochemical, geological, and geophysical data". Journal of Volcanology and Geothermal Research. 168 (1–4): 1–27. Bibcode:2007JVGR..168....1E. doi:10.1016/j.jvolgeores.2007.06.004.
  18. ↑ Ellis, S.; Beavan, J.; Eberhart-Phillips, D.; Stöckhert, B. (July 2006). "Simplified models of the Alpine Fault seismic cycle: stress transfer in the mid-crust". Geophysical Journal International. 166 (1): 386–402. Bibcode:2006GeoJI.166..386E. doi:10.1111/j.1365-246x.2006.02917.x. ISSN   0956-540X. S2CID   55413444.
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