Nadia Lapusta

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Nadia Lapusta
Alma mater Taras Shevchenko National University of Kyiv
Harvard University
Known for Continuum mechanics
Earthquake physics
Scientific career
Institutions California Institute of Technology

Nadia Lapusta is a Professor of Mechanical Engineering and Geophysics at the California Institute of Technology. She designed the first computational model that could accurately and efficiently simulate sequence of earthquakes and interseismic slow deformation on a planar fault in a single consistent physical framework. [1]

Contents

Education and early career

Lapusta was born in Ukraine. She completed her bachelor's degree at Taras Shevchenko National University of Kyiv, where she graduated with the highest honours in 1994. [2] [3] She moved to America for her doctoral studies, earning a Master's degree in 1996 and a PhD in 2001. Her doctoral work considered the dynamics of frictional sliding on planar interfaces and was supervised by James R. Rice. [4] During her doctoral studies she was awarded an outstanding student presentation award from the American Geophysical Union and Harvard University Certificate of Distinction in Teaching. [2] Her thesis was awarded the Nicholas Metropolis Award for Outstanding Doctoral Thesis Work in Computational Physics from the American Physics Society. [2]

Research and career

Lapusta joined California Institute of Technology as an Assistant Professor of Mechanical Engineering and Geophysics in 2002. [5] She is a member of the Caltech Seismological Laboratory and the Mechanical and Civil Engineering Faculty in the division of Engineering and Applied Science. [6] [7] Her research group focuses on studying mechanics of geomaterials, fundamentals of friction, solid-fluid interactions and earthquake source processes. [8] In particular, Lapusta is interested in the mechanics and physics of seismic deformation and aseismic creep, and uses both analytical and numerical modelling to study friction and fracture phenomena. [9] She was awarded a National Science Foundation CAREER Award to develop an interdisciplinary framework for the fundamental understanding and prediction of earthquake processes. [10]

The unique computational framework developed by Lapusta and collaborators have provided transformative insights into the nature of earthquake processes and fault slip across scales. [1] The model can predict the seismic (fast) and aseismic (slow) behaviour. [1] She used this model to simulate various fault behaviours, including earthquake nucleation, post-seismic slip and inter-seismic deformation. [11] Using a single model to simulate all fault behaviours made it possible for Lapusta et al. to demonstrate that during an earthquake the supposedly stable zones behave differently when penetrated by earthquake ruptures, and can in fact contribute to the generation of massive earthquakes through dynamic weakening. [12] [13] Her model could qualitatively reproduce the 2011 Tōhoku earthquake. [11] uncovering the critical role of small scale frictional and hydromechanical processes and pointing to complex feedback interactions between fault slip, friction, and heterogeneous hydraulic properties that may qualitatively and quantitatively alter fault response from what may be inferred from small scale experiments [11] Lapusta's work on small repeating earthquakes, interaction of seismic and aseismic slip in complex fault structures, and dynamic weakening that may potentially control the final size of an earthquake following its nucleation, has demonstrated the importance of rigorous mechanics-based modelling of earthquake processes, and how this may potentially be very informative to seismic hazard calculations particularly when data is scarce as it is the case for large earthquakes. For example, Lapusta studied the large areas of aseismic creep after the 2007 Peru earthquake, which can act to lower the seismic hazard in a particular region. [14] Her computational work also includes using probabilistic inversion tools to understand tsunamis generated in during subduction zone earthquakes in deep-ocean trenches in Japan and Chile. [15]

In collaboration with Ares Rosakis at Caltech, Lapusta is co-leading an National Science Foundation research project that aims at coupling rigorous computational tools and laboratory earthquake experiments to elucidate the fundamental nature of the dynamic friction laws and frictional slip modes across scales. [16] Dynamic friction determines how earthquake ruptures move along faults such as the San Andreas Fault, but is still largely misunderstood. [16] Lapusta applies her continuum mechanics based computational models to understand the interplay between friction, stress evolution, past seismicity, and future behaviour of fault segments. [17]

In 2017 Lapusta was awarded the Caltech Graduate Student Council Mentoring Award. [18] She was the vice chair of the Southern California Earthquake Center Board of Directors, and currently co-leads its interdisciplinary working group on Fault and Rock Mechanics. She has also been involved with the National Academy of Engineering Frontiers of Engineering program.

Related Research Articles

Fault (geology) Fracture or discontinuity in rock across which there has been displacement

In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within the Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep.

Garlock Fault

The Garlock Fault is a left-lateral strike-slip fault running northeast–southwest along the north margins of the Mojave Desert of Southern California, for much of its length along the southern base of the Tehachapi Mountains.

Fault mechanics Field of study that investigates the behavior of geologic faults

Fault mechanics is a field of study that investigates the behavior of geologic faults.

Aseismic creep

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.

Earthquake engineering Interdisciplinary branch of engineering

Earthquake engineering is an interdisciplinary branch of engineering that designs and analyzes structures, such as buildings and bridges, with earthquakes in mind. Its overall goal is to make such structures more resistant to earthquakes. An earthquake engineer aims to construct structures that will not be damaged in minor shaking and will avoid serious damage or collapse in a major earthquake. Earthquake engineering is the scientific field concerned with protecting society, the natural environment, and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels. Traditionally, it has been narrowly defined as the study of the behavior of structures and geo-structures subject to seismic loading; it is considered as a subset of structural engineering, geotechnical engineering, mechanical engineering, chemical engineering, applied physics, etc. However, the tremendous costs experienced in recent earthquakes have led to an expansion of its scope to encompass disciplines from the wider field of civil engineering, mechanical engineering, nuclear engineering, and from the social sciences, especially sociology, political science, economics, and finance.

Clarence Roderic Allen was a geologist who studied seismology.

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.

Thomas H. (Tom) Heaton is an American seismologist, known for his influential contributions in earthquake source physics and earthquake early warning. Currently he is the professor of geophysics and civil engineering at Caltech and one of the world’s leading experts on seismology.

Ares J. Rosakis

Ares J. Rosakis Theodore von Kármán Professor of Aeronautics and Professor of Mechanical Engineering at the California Institute of Technology. He was also the fifth Director of the Graduate Aerospace Laboratories, known as (GALCIT), and formerly known as Guggenheim Aeronautical Laboratory, and was the Otis Booth Leadership Chair, of the Division of Engineering and Applied Science.

An earthquake rupture is the extent of slip that occurs during an earthquake in the Earth's crust. Earthquakes occur for many reasons that include: landslides, movement of magma in a volcano, the formation of a new fault, or, most commonly of all, a slip on an existing fault.

Xianshuihe fault system

The Xianshuihe fault system is a major active sinistral (left-lateral) strike-slip fault zone in southwestern China, at the eastern edge of the Tibetan Plateau. It has been responsible for many major earthquakes, and is one of the most seismically active fault zones in this part of China.

An asperity is an area on an active fault where there is increased friction, such that the fault may become locked, rather than continuously slipping as in aseismic creep. Earthquake rupture generally begins with the failure of an asperity, allowing the fault to move.

Azita Emami Engineering professor

Azita Emami-Neyestanak is the Andrew and Peggy Cherng Professor of Electrical Engineering and Medical Engineering at CalTech. Emami works on low-power mixed-mode circuits in scalable technologies. She is Executive Officer of the Department of Electrical Engineering and an investigator in the Heritage Medical Research Institute.

Michelle Effros is the George Van Osdol Professor of Electrical Engineering at the California Institute of Technology. She has made significant contributions to data compression.

Emily Brodsky Geophysicist

Emily E. Brodsky is a Professor of Earth Sciences at the University of California, Santa Cruz. She studies the fundamental physical properties of earthquakes, as well as the seismology of volcanoes and landslides.

Jean Marie Carlson is a Professor of Complexity at the University of California, Santa Barbara. She studies robustness and feedback in highly connected complex systems, which have applications in a variety of areas including earthquakes, wildfires and neuroscience.

Joan S. Gomberg is a research geophysicist at the United States Geological Survey. She serves as an adjunct professor at the University of Washington. She is interested in subduction zone science, and studies how earthquakes trigger each other and how faults can slip. Gomberg is a Fellow of the American Geophysical Union. She was the first person to demonstrate how dynamic stress associated with seismic waves can trigger other earthquakes.

Michel Campillo is a French geophysicist and seismologist. He was born in 1957 and grew up in Chambon sur Lignon.

Michael Ortiz is an American scientist and researcher in the fields of structural, continuum and computational mechanics and is a Frank and Ora Lee Marble professor of aeronautics and mechanical engineering at California Institute of Technology.

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References

  1. 1 2 3 "Caltech Division of Engineering and Applied Science | News | Greater Insight into Earthquake Cycles". eas.caltech.edu. Retrieved 2019-04-13.
  2. 1 2 3 "2002 Outstanding Doctoral Thesis Work". www.aps.org. Retrieved 2019-04-13.
  3. ↑ "Caltech Division of Engineering and Applied Science | ENGenious | Issue 3 | New Faculty". eas.caltech.edu. Retrieved 2019-04-13.
  4. ↑ Lapusta, Nadia (2001). "Elastodynamic analyses of sliding with rate and state friction". Ph.D. Thesis. Bibcode:2001PhDT.......125L.
  5. ↑ "Nadia Lapusta | Caltech Directory". directory.caltech.edu. Retrieved 2019-04-13.
  6. ↑ "Nadia Lapusta - Caltech Seismological Laboratory". www.seismolab.caltech.edu. Retrieved 2019-04-13.
  7. ↑ "Caltech Mechanical and Civil Engineering | Nadia Lapusta". www.mce.caltech.edu. Retrieved 2019-04-13.
  8. ↑ "Nadia Lapusta - Caltech". lapusta.caltech.edu. Retrieved 2019-04-13.
  9. ↑ "Nadia Lapusta". web.gps.caltech.edu. Retrieved 2019-04-13.
  10. ↑ "NSF Award Search: Award#0548277 - CAREER: Integrated Program of Multidisciplinary Education and Research in Mechanics and Physics of Earthquakes". www.nsf.gov. Retrieved 2019-04-13.
  11. 1 2 3 "Faulty behavior: New earthquake fault models show that 'stable' zones may contribute to the generation of massive earthquakes". ScienceDaily. Retrieved 2019-04-13.
  12. ↑ Noda, Hiroyuki; Lapusta, Nadia (2013-01-24). "Stable creeping fault segments can become destructive as a result of dynamic weakening". Nature. 493 (7433): 518–521. doi:10.1038/nature11703. ISSN   0028-0836. PMID   23302798. S2CID   4429849.
  13. ↑ Nadia Lapusta; Noda, Hiroyuki (January 2013). "Stable creeping fault segments can become destructive as a result of dynamic weakening". Nature. 493 (7433): 518–521. doi:10.1038/nature11703. ISSN   1476-4687. PMID   23302798. S2CID   4429849.
  14. ↑ "Caltech Division of Engineering and Applied Science | News | Aseismic Slip as a Barrier to Earthquake Propagation". eas.caltech.edu. Retrieved 2019-04-13.
  15. ↑ "Caltech Division of Engineering and Applied Science | News | Winners of the 2016 Demetriades - Tsafka - Kokkalis Prizes Announced". eas.caltech.edu. Retrieved 2019-04-13.
  16. 1 2 "NSF Award Search: Award#1651235 - Investigating dynamic friction using earthquake ruptures produced in the laboratory". www.nsf.gov. Retrieved 2019-04-13.
  17. ↑ "Keynote speakers | MultiScale Material Science for Energy and Environment". umi.mit.edu. Retrieved 2019-04-13.
  18. ↑ "Caltech Division of Engineering and Applied Science | News | Professor Lapusta Receives GSC Mentoring Award". eas.caltech.edu. Retrieved 2019-04-13.
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