August 2012 Brawley Earthquake Swarm
A Ml 5.5 earthquake occurred at 1:57PM on August 26th, 2012, and was preceeded by nearly 200 events ranging Ml 1.4 - Ml 5.3. The earthquakes are occurring on a northeast striking fault zone located about 6 km north of the northwest end of the mapped Imperial Valley fault. This is within the area called the Brawley Seismic Zone. The BSZ extends from the northern end of the Imperial fault to the southern end of the San Andreas fault.
Click here to read the executive summary on the Southern California Seismic Network.
Seismologists Discover Maze-like Path of 2012 Mw 8.6 Sumatra Earthquake
A team, including Seismo Lab assistant professor of seismology Jean-Paul Ampuero and graduate student Lingsen Meng (first author of the paper), used ground-motion recordings gathered by networks of sensors in Europe and Japan, and an advanced source-imaging technique developed in Caltech's Seismological Laboratory as well as the Tectonics Observatory to piece together a picture of the 2012 Mw 8.6 Sumatra Earthquake's complex rupture process. Their research appears in the July 19 issue of Science Express, an online publication ahead of print for Science Magazine.
Click here to read Caltech's article.
Click here for the article published in Science Express.
SSA Announces 2012 Student Presentation Award Winners
Seismo Lab graduate student, Lingsen Meng, was awarded the student prize for his paper presented at the 2012 Annual Meeting of the Seismological Society of America. The award is in recognition of Lingsen's excellent scientific capabilities and the manner in which he conveyed his results and interpretations to fellow scientists.
Click here to view all of the recpients of the 2012 SSA Student Presentation Award
Dr. Hiroo Kanamori Elected Foreign Associate of the National Academy of Sciences
Dr. Hiroo Kanamori, John E. and Hazel S. Smits
Professor of Geophysics, Emeritus was elected foreign associate of the National Academy of Sciences. The 21 foreign associates are from 15 countries in recognition of their distinguished and continuing achievements in original research. They are nonvoting members of the Academy, with citizenship outside the United States.
Click here to read the News From the National Academy of Sciences.
Seismo Faculty and Students Enjoy Retreat
Twenty-six members of the Seismo Lab spent the day at the Castaic Lake State Recreation Area in
Castaic, CA for this year's 2012 Student Faculty Retreat. The graduate students, post-docs, faculty, and staff on the
retreat enjoyed a morning hike along some of the park's trails and a
fun-filled afternoon of team-building games along the lakefront. The main
event was the "Amazing Race: Seismo Lab Student Faculty Retreat Edition",
for which each retreat participant received a certificate of completion.
The afternoon was topped off by an awards ceremony in which the winning teams for each game received prizes. A four-course al fresco dinner at a
local Italian restaurant completed the retreat.
Lean more about the Seismo Lab Annual Student Faculty Retreat http://www.seismolab.caltech.edu/daily.html
4/11/2012 (Mw 8.6), Offshore Sumatra, Indonesia Back-Projection Results
The April 11 2012 M8.6 earthquake off-shore Sumatra is a record-breaking event in many respects:
it is the largest strike-slip earthquake and the largest intraplate earthquake ever recorded.
High-resolution source imaging by back-projection of high-frequency teleseismic array data (by Lingsen Meng, Jean-Paul Ampuero, and Yingdi Luo) shows that this is also one of the most
complicated ruptures ever witnessed by modern seismology. It involved rupture on at least three
different faults in a system of almost orthogonal faults.
Click here to read the article on the Techtonics Observatory website.
Seismo Lab Mineral Physics Researchers Study Properties of Iron in Earth's Core
A team, including Seismo Lab assistant professor of mineral physics Jennifer Jackson and graduate student Caitlin Murphy (first author of the paper), has honed in on how iron behaves under the conditions found deep in the earth by conducting extremely high-pressure experiments on the element. The team used diamond anvil cells (DACs) to squeeze the iron samples, reproducing the types of pressures felt in the earth's core. Their research appears in the December 20 issue of Geophysical Research Letters.
Click here to read Caltech's article.
Click here for the article published in Geophysical Research Letters.
Seismo Lab graduate student Laura Alisic, along with two other scientists, has been awarded the Computational Science and Engineering Prize 2011 by Springer for outstanding work on simulating global mantle convection at tectonic plate boundary-resolving scales.
Congratulations, Laura! Click here for more about Laura.
Caltech Awarded $2 Million to Develop Earthquake Early Warning System
The California Institute of Technology has been awarded $2 million of a $6 million grant by the Gordon and Berry Moore Foundation to help develop a prototype earthquake early warning system for the Pacific Coast of the United States. The grant will allow seismologists at Caltech, the University of California, Berkeley, and University of Washington, Seattle, in collaboration with the U.S. Geological Survey, to learn about the science of earthquakes and the best way to capture and analyze seismic data in order to give schools, utilities, industries and the general public as much time as possible—most likely seconds to several minutes—before the ground begins to shake.
“The Foundation’s grant is a huge contribution to moving forward the science of earthquake early warning systems,” said Thomas Heaton, director of the Earthquake Engineering Research Laboratory and professor of geophysics and of civil engineering at Caltech.
Click here to read the Gordon and Betty Moore Foundation press release.
Seismo Lab graduate student Brent Minchew was given an Achievement Rewards for College Scientists Foundation Scholar Award. This award is for outstanding science, engineering and medical research graduate and undergraduate students who are citizens of the United States.
Congratulations, Brent! Click here for more about Brent.
M5.8 Earthquake Hits Virginia on August 23, 2011 at 1:51 p.m. EDT
Community Seismic Network
Robert W. Clayton, Professor of Geophysics, is working on a New Scientific Opportunity USB3 - Component Accelerometers. We are developing a new earthquake monitoring (seismic network) system, Community Seismic Network (CSN) based on a dense array of low-cost sensors. The goal of the system is to produce block-by-block estimates of strong ground shaking. The information from these sensors will be sent to central computers that will process the data and produce localized estimates of ground shaking on a block-by-block basis - essentially, motions of the evolving seismic wave field during local earthquakes. This information will guide emergency responders and promises to lead to a new level of understanding of the physics of earthquakes and their impact on Southern California. The development of the new network is partially supported by the National Science Foundation (NSF). Learn more
Seismo Lab graduate student Lingsen Meng was presented with the Comprehensive Nuclear-Test-Ban Treaty Organization's Best Young Scientist Award for two presentations he made on the Tohoku-Oki earthquake at the CTBTO 2011 Science and Technology conference held in Vienna, Austria.
Congratulations, Lingsen! Click here for more about Lingsen.
Seismologist Reflects on his Firsthand Experience of the Japanese Earthquake
Eminent seismologist Hiroo Kanamori, Caltech's Smits Professor of Geophysics, Emeritus, has been studying the movement of the earth his entire career. On March 11 he was in Tokyo, experiencing firsthand the largest earthquake in the country's recorded history. For the full story, click here.
Simons Argues Against Hazard Prevention Cuts
Less than two weeks after a 9.0 earthquake and tsunami devastated a large swath of Japan, Caltech geophysicist Mark Simons, in today's Wall Street Journal, calls attention to federal budget proposals that would cut funding for prevention technologies. "Mitigating against future disasters depends on monitoring hazardous regions (earthquake faults, volcanoes, landslides and so on) and preparing to survive and recover once catastrophe strikes," Simons says in the opinion piece. By cutting funding for advanced early-warning and response technologies, our country's long-term security is jeopardized, he argues. For the full story, click here.
Looking Inside the San Andreas
A new Earthquake study could provide the best idea yet of how the Big One will affect the Southland.
Please click on the following link to read the entire article in the LA Times.
New View of Tectonic Plates
PASADENA, Calif.—Computational scientists and geophysicists at the University of Texas at Austin and the California Institute of Technology (Caltech) have developed new computer algorithms that for the first time allow for the simultaneous modeling of the Earth's mantle flow, large-scale tectonic plate motions, and the behavior of individual fault zones, to produce an unprecedented view of plate tectonics and the forces that drive it.
A paper describing the whole-earth model and its underlying algorithms will be published in the August 27 issue of the journal Science and also featured on the cover.
The work "illustrates the interplay between making important advances in science and pushing the envelope of computational science," says Michael Gurnis, the John E. and Hazel S. Smits Professor of Geophysics, director of the Caltech Seismological Laboratory, and a coauthor of the Science paper.
The paper, "The Dynamics of Plate Tectonics and Mantle Flow: From Local to Global Scales," was also coauthored by Georg Stadler, Carsten Burstedde, Lucas C. Wilcox and Omar Ghattas all at the University of Texas at Austin and Laura Alisic of Caltech. The work was supported by the NSF, the Department of Energy's Office of Science, and—at the Caltech Tectonics Observatory—by the Gordon and Betty Moore Foundation.
Click here to read Kathy Svitil's full article.
Click here to visit Science magazine's home page.
Tribute to Professor Thomas J. Ahrens, Fletcher Jones Professor of Geophysics, Emeritus
Thomas J. Ahrens, one of the leading figures in mineral physics, geophysics, and planetary sciences during the Twentieth Century and a member of the Seismological Laboratory, passed away on November 24, 2010 at the age of 74. His many former students, collaborators and Caltech friends will sorely miss him. Ahrens spent more than forty years at Caltech and was the Fletcher Jones Professor of Geophysics, Emeritus when he passed away. His vast research accomplishments and impact touched on the origin, differentiation and evolution of the Earth and planets. An experimentalist at heart, he was widely known for starting and leading the Lindhurst Laboratory of Experimental Geophysics. Through the more than thirty graduate students and fifteen post docs and visiting associates he mentored, his impact on science will be felt for many years to come. To read and print the entire tribute, click here.
Reaction to Mantle Plume Discovery
According to a review by Richard A. Kerr in Science magazine, "Mantle plumes--tall columns of hot rock rising to feed volcanic hot spots like Hawaii--are either fundamental components of Earth's heat-shedding machinery that reshape the surface and perhaps trigger mass extinctions, or they are the figments of some geophysicists' imaginations." His review explores the reactions of the scientific community to an article by Seismo Lab scientists Daoyuan Sun, Don Helmberger, and Michael Gurnis that was published in Geophysical Research Letters on May 4, 2010. In the article, Sun et al. posited the existence of a mantle plume under southern Africa.
Click here to read Science magazine's review.
Caltech's Mineral Physicists Find Unusual Properties of Minerals at Earth's Core-Mantle Boundary
Using a diamond-anvil cell to recreate the high pressures deep within the earth, researchers at Caltech have found unusual properties in an iron-rich magnesium- and iron-oxide mineral that may explain the existence of several ultra-low velocity zones (ULVZs) at the core-mantle boundary. A paper about their findings was published in a recent issue of Geophysical Research Letters.
Click here for Caltech's article.
New Faculty Victor Tsai to Join the Seismological Laboratory in the GPS Division
Victor Tsai, Assistant Professor of Geophysics, will be joining the division in July 2011. Victor was born in Massachusetts but grew up mostly in the San Francisco Bay area. As an undergraduate at Caltech, he became interested in geophysics and did research on atmospheric/solid-earth coupling and the stability of earth rotation, graduating with a BS in geophysics. While pursuing his Ph.D. at Harvard University, he broadened his research interests to include earthquake dynamics, glacier mechanics, solid-fluid interactions, and seismic noise tomography. As a postdoctoral fellow at the United States Geological Survey, he is continuing some of this work while also investigating the physical processes that generate seismic noise.
Seismo Lab graduate student Brent Minchew has been awarded the NASA Earth and Space Science Fellowship (NESSF) for his proposal, "Temperate Glacier Observations with L-Band SAR". The National Aeronautics and Space Administration (NASA) received a total of 331 applications to this fellowship program announced in November 2010 in Earth Science Research and selected 57 for award.
Congratulations, Brent! Click here for more about Brent.
The 2011 M9.0 Tohoku-oki Earthquake Provides Unprecedented Observations
For updated information about the 2011 Tohoku-oki earthquake, please click here.
The tragic M9.0 Tohoku-oki earthquake in Japan, which occurred on March 11, 2011, generated an extraordinary volume of observations that will be used to further our understanding of large seismic events. The devastating images, video, and reports showing widespread destruction serve as a catalyst to the scientists at Caltech to further strengthen our resolve to mitigate hazards associated with damaging earthquakes. Caltech scientists and collaborators at JPL continue to analyze the data, with the aim of describing the earthquake with the highest fidelity possible.
We show a preliminary animation derived by back-projection of seismic waves, which models the initial 180 seconds of the earthquake rupture. Created by Lingsen Meng and Jean-Paul Ampuero of Caltech, the model uses data collected from USArray seismic stations located in the United States (in addition to European stations), and shows that ~100 seconds into the earthquake, the fault rupture undergoes a complex change, where the rupture front splits bilaterally north and south.
Animation showing back-projection of the teleseismic waves to their source. Note the north-south bilateral split of the fault rupture, with significant displacement of the fault continuing to the south, while mild to moderate displacement continues north.
High frequency analysis of the teleseismic records by Caltech Seismological Laboratory seismologists Risheng Chu and Don Helmberger further confirm the bilateral fault rupture as seen in the back-projection animation above, and the data demonstrate a slower than average rupture velocity, indicating this fault took longer to rupture than other faults of similar size and geometry.
Ray count and analysis of high-frequency waveforms calculate 90% of the energy was released during the first 250 seconds of the fault rupture. This correlates to the slow speed of the bilateral fault rupture, shown in the previous animation, which models the speed of the rupture at ~2.8km/second. This is slightly faster than the 2004 Great Sumatra Earthquake, but still slower than typical fault rupture speeds.
Caltech scientists Shengji Wei and the members of the ARIA project (a collaboration between Caltech and JPL), along with Anthony Sladen of Geoazur, have created a model of the distribution of slip on the subsurface fault. The model is derived by combining observations from long distance teleseismic body waves and near source GPS observations. A 3D image of the fault slip can be viewed in Google Earth (link to KML file here: http://www.tectonics.caltech.edu/slip_history/2011_taiheiyo-oki/tohoku11-joint.kml ), and projects the fault rupture in three dimensions, which can be viewed from any point of reference. The analysis shows that the rupture originated ~24 km (15 miles) deep, and the maximum slip on the fault was 100 feet, ultimately thrusting the island of Japan as much as 5m (16 feet) east from its location before the earthquake.
The graphic above projects the fault geometry above the surface of the earth in three dimensions. Hot/cold colors correlate to maximum/minimum displacements of the fault, respectively. Click on the image above to download the Google Earth KML file.
Caltech scientists, in conjunction with Geoazur in France, have modeled the deadly tsunami by combining GPS and teleseismic data (http://www.tectonics.caltech.edu/slip_history/2011_taiheiyo-oki), creating an animation which is solved under the non-linear shallow water approximation using a finite difference code.
An animation depicting the tsunami as it traverses the Pacific Ocean. The difference in red and blue colors represent the peaks and troughs of the waves, respectively. Tsunamis generated by earthquakes rarely exceed 2 meters (6 feet) on average. This tsunami had a maximum observed run-up of 13 m (43 ft) in some areas of Japan, and caused millions of dollars of damage as far away as Hawaii and California. Although one fatality occurred near Crescent City, CA, the tsunami caused several thousand fatalities in Japan. The resultant damage and fatalities caused by the tsunami far exceeded the damage and lives lost due to earthquake shaking. This animation was created by a collaboration of the Tectonics Observatory at the Caltech Seismological Laboratory, GeoAzur (France), California Earthquake Authority, and CNRS (France).
The deadly Tohoku-oki earthquake occurred at the boundary between the Eurasian Plate and the Pacific Plate; this is a plate boundary where the plates are converging at a rate of ~8cm/year, respectively. No earthquake of this magnitude had occurred in this area within recorded history, and many in the scientific community did not think a M9 or larger was possible in this area. This event will change the way seismologists and geophysicists view subduction zone dynamics in the future.
Maximum fault slip, shown in red, was nearly 30 m (90 feet). Surface projection of the fault plane slip distribution is shown above. Red dots are plate boundaries, whereas grey dots are aftershocks during the first day. The mainshock epicenter is denoted by the red star. This image was modeled by Shengji Wei, Anthony Sladen, and the ARIA group (Caltech-JPL).
M5.4 Borrego Earthquake July 7, 2010
A M5.4 earthquake occurred in southern California at 4:53 pm (Pacific Time) about 30 miles south of Palm Springs, 25 miles southwest of Indio, and 13 miles north-northwest of Borrego Springs. The earthquake occurred near the Coyote Creek segment of the San Jacinto fault, which is one of the strands of the San Jacinto fault. The earthquake exhibited sideways horizontal motion to the northwest, consistent with slip on the San Jacinto fault. It was followed by more than 60 aftershocks of M>1.3 during the first hour. Seismologists expect continued aftershock activity.
This M5.4 earthquake follows the 4th of April 2010, Easter Sunday, Mw7.2 earthquake, located about 125 miles to the south, well south of the US Mexico international border. A M4.9 earthquake occurred in the same area on June 12th at 8:08 pm (Pacific Time). Thus this section of the San Jacinto fault remains active.
Also, visit daretoprepare.org for up-to-date information on how to protect yourself, your family, and your property.
Congratulations to GPS Division Graduates
Congratulations to the Geological & Planetary Sciences Division graduates! In particular, we would like to recognize Geophysics/Seismological Laboratory doctoral graduates Ravi Kanda, Lijun Liu, and Sarah Minson.
Don Helmberger Quoted on Magma Plume Discovery
A June 18 story on OurAmazingPlanet looked at the discovery of a magma plume under southern Africa and quoted study coauthor Don Helmberger.
Learn more by reading Brett Israel's article, "Magma Plume Discovered Under Southern Africa" from June 18, 2010 on OurAmazingPlanet.
Ting Chen Granted the 2009 National Award for Outstanding Self-financed Chinese Students Studying Abroad
Seismo Lab graduate student Ting Chen has been awarded the 2009 National Award for Outstanding Self-financed Chinese Students Studying Abroad by the China Scholarship Council (CSC). This award was founded by the Chinese government in 2003 with the purpose of rewarding the academic excellence of self-financed Chinese students studying overseas. Only those with outstanding performance in their Ph.D. studies are considered for the award, and no more than 500 students are granted the award each year.
Congratulations, Ting! Click here for more information about Ting.
YoungHee Kim Awarded the Anadarko/SEG and the KUSCO-KSEA Scholarships
Seismo Lab graduate student YoungHee Kim has been awarded the Anadarko/SEG (Society of Exploration Geophysicists) Scholarship for the 2010-2011 school year. The scholarship is sponsored by Anadarko Petroleum. Geosciences students worldwide are considered for this scholarship.
YoungHee has also been awarded the KUSCO-KSEA Scholarship for graduate students in the United States. This scholarship is to recognize outstanding graduate students who have excelled in the field of science and engineering as well as in extracurricular activities, including community service, and who have demonstrated a potential for becoming leaders in the scientific community for closer cooperation between the U.S. and Korea.
Congratulations, YoungHee! Click here for more information about YoungHee.
"The Biggest One" - Hiroo Kanamori Interviewed on the 50th Anniversary of Chile's 1960 Magnitude 9.5 Earthquake
Hiroo Kanamori, Caltech Professor Emeritus is interviewed by Nature on the 50th anniversary of Chile's 1960 magnitude 9.5 earthquake - Nature magazine talks with the experts. Nature magazine's Roff Smith interviews Caltech Professor Emeritus Hiroo Kanamori as he looks back at the largest earthquake ever recorded.
About Hiroo Kanamori: In 1977 Dr. Hiroo Kanamori developed the Moment Magnitude scale, which replaced the Richter scale for measuring earthquakes M5.0 and larger. Using the improved method, scientists were able to obtain more precise measurements of the energy of large earthquakes that occurred in the past, such as the 1960 Chilean earthquake and the 1964 Alaskan earthquake, as well as a better means of studying and analyzing seismic events when they occur.
Learn more by reading Roff Smith's article, "The Biggest One" in Nature's May 5, 2010 edition.
Bin Chen Receives the John C. Jamieson Award
Bin Chen, a Texaco Postdoctoral Fellow, is the 2010 recipient of the John C. Jamieson Award. The Jamieson Award is given for outstanding achievement in the field of high pressure research by a graduate student or postdoctoral researcher. This award is given every year, alternating at the Gordon Research Conference (Research at High Pressure) in one year and the AIRAPT Conference the next year. Bin will accept the award at the GRC this summer. John Calhoun Jamieson (1924 - 1983) was Professor of Geophysics at The University of Chicago. Most of his research used static high pressures. He also performed shock experiments at Los Alamos and SRI International. The John C. Jamieson Memorial Fund, which supports the Award, was established by a number of Jamieson's former students and colleagues. The Fund is managed by Bob Schock, a former postdoc of Jamieson and currently Director of Studies for the World Energy Council (WEC) in London.
Congratulations Bin! More information about Bin can be found on his homepage.
Caltech Seismo Lab Professor Joann Stock Elected a Fellow of the American Geophysical Union February 2010
A Fellow of AGU is a scientist who has attained acknowledged eminence in the geophysical sciences. This honor is bestowed on only 0.1% of the membership in any given year by a committee of 11 Fellows. Click here to learn more
Magnitude 7.2 Earthquake- Baja California, Mexico
The magnitude 7.2 northern Baja California earthquake of Sunday, April 4, 2010, occurred approximately 40 miles south of the Mexico-USA border at shallow depth along the principal plate boundary between the North American and Pacific plates. This is an area with a high level of historical seismicity and has recently been seismically active, though this is the largest event to strike in this area since 1892. This earthquake appears to be larger than the M 6.9 earthquake in 1940 or any of the early 20th century events (e.g., 1915 and 1934) in this region of northern Baja California.
The principal plate boundary in northern Baja California consists of a series of northwest-trending strike-slip faults that are separated by pull-apart basins. The faults are distinct from but parallel to strands of the San Andreas fault system. The April 4 main-shock occurred along a strike-slip segment of the plate boundary that coincides with the southeastern part of the Laguna Salada fault. Aftershocks appear to extend in both directions along this fault5 system from the epicenter of yesterday's event. The aftershock zone extends from the northern tip of the Gulf of California to the Mexico-USA border. There have been more than 1000 aftershocks as of Tuesday, April 6,2010.
Also, visit daretoprepare.org for up-to-date information on how to protect yourself, your family, and your property.
Jennifer Jackson is NSF Faculty Early CAREER Development Awardee
Jennifer Jackson, Assistant Professor of Geophysics, has been selected to receive a NSF Faculty Early CAREER Development Award. The program is a Foundation-wide activity that offers the National Science Foundation's most prestigious awards in support of the early career development activities of those teacher-scholars who most effectively integrate research and education within the context of the mission of their organization. Such activities should build a firm foundation for a lifetime of integrated contributions to re-search and education. Her specific award title is: "Investigations on the elastic and vibrational properties of mantle silicates and oxides." Learn more about Jennifer Jackson's research
Swami Krishnan, Assistant Professor, Wins Earthquake Engineering Research Institute's 2009 Annual Graphics Competition
Congratulations to Swaminathan Krishnan, Assistant Professor of Civil Engineering and Geophysics, whose simulations of earthquakes and structural response has won the Earthquake Engineering Research Institute's 2009 Annual Graphics Competition. View the submission
Laura Alisic NSF-MARGINS Poster Winner
Seismo Lab graduate student Laura Alisic is the National Science Foundation’s MARGINS Student Prize Poster Winner for 2009. She presented her poster, “Ultra-High Resolution and Composite Rheology in Global Mantle Flow”, at the 2009 AGU Fall Meeting. The judges commended her on "An extremely well presented poster on a complex topic by a student in full control of her research. From start to finish, [they] found this poster presentation to be done at a very high professional and scientific level. Superb, eye-catching graphics, logical organization, clear in-person discussion and response to questions. Simply outstanding." The poster can be viewed by clicking the link on nsf-margins.org.
Congratulations, Laura! More information about Laura's research can be found on her web site.
Michael Gurnis Named Director of the Seismological Laboratory
Michael Gurnis, John E. and Hazel S. Smits Professor of Geophysics, was named Director of the Seismological Laboratory, effective July 1, 2009. Dr. Gurnis will continue the tradition of strong leadership that the Seismo Lab has enjoyed over the decades. He brings with him a breadth of experience working with international organizations. He has a dedicated focus on the education and training of new scientists. He balances his students' experience through research in both geo-physical and computational science. Dr. Gurnis served as Associate Director of the Seismological Laboratory from 1995-2003 and is currently Director of Computational Infrastructure for Geo-dynamics (CIG). Learn more about Michael Gurnis' research