(Press-News.org) Contact information: Beth Chee
bchee@mail.sdsu.edu
619-594-4563
San Diego State University
Subterranean 'sedimentary bathtub' amplifies earthquakes
A basin of stiff soil beneath Vancouver might make earthquakes there more severe than expected, a San Diego State University seismologist finds
SAN DIEGO, Calif. (Jan. 21, 2014)— Like an amphitheater amplifies sound, the stiff, sturdy soil beneath the Greater Vancouver metropolitan area could greatly amplify the effects of an earthquake, pushing the potential devastation past what building codes in the region are prepared for. That's the conclusion behind a pair of studies recently coauthored by San Diego State University seismologist Kim Olsen.
Greater Vancouver sits atop a tectonic plate known as the Juan de Fuca Plate, which extends south to encompass Washington and Oregon states. The subterranean region of this plate beneath Vancouver is a bowl-shaped mass of rigid soil called the Georgia Basin. Earthquakes can and do occur in the Georgia Basin and can originate deep within the earth, between 50 and 70 kilometers down, or as shallow as a couple kilometers.
While earthquake researchers have long known that the region is tectonically active and policymakers have enforced building codes designed to protect against earthquakes, those codes aren't quite strict enough because seismologists have failed to account for how the Georgia Basin affects a quake's severity, Olsen said. In large part, that's because until recently the problem has been too computationally complex, he said.
"People have neglected the effects of stiffer soil," Olsen said. "They haven't been able to look at the basin as a three-dimensional object."
The idea to investigate the basin's effect on earthquakes originated with Sheri Molnar, a postdoctoral researcher at the University of British Columbia. She reached out to Olsen, an expert in earthquake simulation, for help modeling the problem. Using supercomputer technology, Olsen has previously simulated the potential effects of a supermassive magnitude 8.0 quake in Southern California.
Using the same technology, Molnar and Olsen coded an algorithm to take into account the stiff-soil geography of the Georgia Basin to see how it would influence the surface effects of a magnitude 6.8 earthquake. They then ran the simulation for both a shallow and a deep quake.
In both simulations they found that the basin had an amplifying effect on motion on the surface, but the amplification was especially pronounced in shallow earthquakes. In the latter scenario, their model predicts that the sedimentary basin would cause the surface to shake for approximately 22 seconds longer than normal.
"The deep structure of the Georgia Basin can amplify the ground motion of an earthquake by a factor of three or more," Olsen said. "It's an irregularly shaped bathtub of sediments that can trap and amplify the waves."
The deep and shallow studies were published today in the Bulletin of the Seismological Society of America.
Current building codes in Vancouver don't take into account this amplification, Olsen added, meaning many buildings in the region would be in danger if a large earthquake were to hit.
Vancouver isn't the only large metropolis built atop sedimentary basins. Los Angeles and San Francisco, too, sit on basins similar to the Georgia Basin. Olsen is currently investigating how major earthquakes along the San Andreas Fault would be affected by these basins.
He hopes that city planners can use this knowledge to update their building codes to reflect the amplifying geography beneath their feet.
"That's always going to be the goal, to make structures safer and to mitigate the damage in the future," Olsen said.
INFORMATION:
About San Diego State University
San Diego State University is a major public research institution offering bachelor's degrees in 89 areas, master's degrees in 78 areas and doctorates in 21 areas. The university provides transformative experiences, both inside and outside of the classroom, for its 34,000 students. Students participate in research, international experiences, sustainability and entrepreneurship initiatives, and a broad range of student life and leadership opportunities. The university's rich campus life features opportunities for students to participate in, and engage with, the creative and performing arts, a Division I athletics program and the vibrant cultural life of the San Diego region. For more information, visit http://www.sdsu.edu.
Subterranean 'sedimentary bathtub' amplifies earthquakes
A basin of stiff soil beneath Vancouver might make earthquakes there more severe than expected, a San Diego State University seismologist finds
2014-01-22
ELSE PRESS RELEASES FROM THIS DATE:
Emergency treatment takes longer for heart attack victims during off-hours
2014-01-22
Emergency treatment takes longer for heart attack victims during off-hours
ROCHESTER, Minn. — Jan. 21, 2014 — More people die and emergency hospital treatment takes longer for heart attack victims who arrive at the hospital during off-hours (nights and weekends), compared ...
White, green or black roofs? Berkeley Lab report compares economic payoffs
2014-01-22
White, green or black roofs? Berkeley Lab report compares economic payoffs
Looking strictly at the economic costs and benefits of three different roof types—black, white and "green" (or vegetated)—Lawrence Berkeley National Laboratory (Berkeley Lab) ...
Exposure to cold temperatures can help boost weight loss
2014-01-22
Exposure to cold temperatures can help boost weight loss
Regular exposure to mild cold may be a healthy and sustainable way to help people lose weight, according to researchers writing in the Cell Press publication Trends in Endocrinology & Metabolism on January 22nd. On ...
Parental exposure to THC Linked to drug addiction, compulsive behavior in unexposed offspring
2014-01-22
Parental exposure to THC Linked to drug addiction, compulsive behavior in unexposed offspring
Mount Sinai study pinpoints molecular and neurobiological effects of THC, the main psychoactive ingredient in marijuana
New York, NY ...
Sneak preview of Survey Telescope treasure trove
2014-01-22
Sneak preview of Survey Telescope treasure trove
VST images the Lagoon Nebula
The VLT Survey Telescope (VST) at ESO's Paranal Observatory in Chile has captured this richly detailed new image of the Lagoon Nebula. This giant cloud of gas and dust is creating intensely bright young stars, ...
Stanford researchers reveal more about how our brains control our arms
2014-01-22
Stanford researchers reveal more about how our brains control our arms
Recording the neural activity of monkeys as they plan to reach, or just react, will help engineers design better brain controlled prosthetic limbs.
Ready, set, go.
Sometimes that's how ...
Carsey Institute: 39 percent of unemployed Americans are seeking work for 6+ months
2014-01-22
Carsey Institute: 39 percent of unemployed Americans are seeking work for 6+ months
New UNH research looks at long-term unemployment in wake of the recession
DURHAM, N.H. – Thirty-nine percent of unemployed Americans are experiencing long-term unemployment ...
Long-term follow-up shows need for new chemotherapy strategies for rectal cancer
2014-01-22
Long-term follow-up shows need for new chemotherapy strategies for rectal cancer
Results of EORTC trial 22921 at 10.4 years median follow-up
Appearing in Lancet Oncology, long term results of EORTC trial 22921 with 10.4 years median follow-up show ...
Deepwater Horizon: Identifying harmful elements of persisting oil
2014-01-22
Deepwater Horizon: Identifying harmful elements of persisting oil
On 20 April 2010, a floating oil rig in the Gulf of Mexico called Deepwater Horizon suddenly exploded, leading to the largest accidental marine oil disaster in the world. ...
Asthma: DMP is largely consistent with guidelines
2014-01-22
Asthma: DMP is largely consistent with guidelines
Current guidelines are more detailed regarding some aspects of treatment
On 22 January 2014 the German Institute for Quality and Efficiency in Health Care (IQWiG) published the ...
LAST 30 PRESS RELEASES:
Ultrafast untethered levitation device utilized squeeze film for omni-directional transport
Cancer cells can evade anti-cancer drugs by entering and surviving within bone marrow fibroblasts
Clarifying medical images using next-level pixel-particle analogy
What exactly is Long COVID? New UCLA research shows the answer depends on whom you ask
Work impairment and financial outcomes among adults with vs without long COVID
Hospital financial health and provision of obstetric and neonatal intensive care unit services
Studying terrestrial rocks to prepare techniques for Mars
Tiny ants crack the secret to perfect teamwork
Scientists find a microbial molecule that restores liver and gut health
Regulation of the temperature stability in ordered olivine microwave dielectric ceramics with low-loss for dielectric resonant antenna
Core-cladding-like phosphor ceramics wafer: a path to ultra-high luminance
Exercise may slow epigenetic aging
RSNA AI challenge models can independently interpret mammograms
Embargoed study: Breaking the link between alcohol use and pancreatic cancer
Why common blood pressure readings may be misleading – and how to fix them
Neural navigation: FAU engineers, sensing institute map brain’s blood flow
“Skin in a syringe” a step towards a new way to heal burns
BTI, Meiogenix and FFAR announce $2 million breakthrough tomato genetics collaboration
Better calibration for cuff-based blood pressure readings
The future of ‘personalized’ cancer treatment: Antitumor mRNA-based vaccines
Common food thickeners – long thought to pass right through us – are actually digested
Off-the-shelf cancer vaccine elicits strong immune response in patients with pancreatic and colorectal cancer
New strategy to boost the effect of immunotherapy in the most aggressive form of lung cancer
Counties with animal feeding operations have more air pollution, less health insurance coverage
Mirror-like graphite films break records in strength and conductivity
AI uncovers new antibiotics in ancient microbes
AI meets CRISPR for precise gene editing
New method to synthesize carbohydrates could pave the way to biomedical advances
Plants feed through one-way routes
3D-printed kidney tumors show potential for more targeted treatment
[Press-News.org] Subterranean 'sedimentary bathtub' amplifies earthquakesA basin of stiff soil beneath Vancouver might make earthquakes there more severe than expected, a San Diego State University seismologist finds