(Press-News.org) Causal relationship between rainfall and earthquakes detailed
This review article explores natural crustal earthquakes associated with the elements of the hydrologic cycle, which describes the continuous movement of water on, above and below the surface of the Earth, including hurricanes and typhoons. The theory of hydroseismicity, first articulated in 1987, attributes most intraplate and near-intraplate earthquakes, to the dynamics of the hydrological cycle.
The Hydroseismicity hypothesis suggests variations in rainfall affect pore-fluid pressure at depth and can trigger earthquakes in areas already under stress and near failure. This report cites documentation of metrological events -- rainfall, stream flow, hurricanes – and observed seismic activity by more than 20 research teams across five continents, providing thorough testing and support of the Hydroseismicity hypothesis.
The authors suggest that the reported correlations between meteorological events and seismicity indicate the need for more local and regional earthquake monitoring networks as well as additional stream gauging stations. In the future it should be possible to discover and quantify causal relationships between earthquakes and meteorological parameters when better focal depths and more stream gauging stations become available. Groundwater hydrology measurements and earthquake monitoring and forecasting might eventually complement each other.
Corresponding author: John K. Costain, Virginia Tech, costain@vt.edu
"An Overview of Hydroseismicity Research Results from 1987 to 2009," by John K Costain, Ph.D. and G. A Bollinger of Virginia Tech.
New evidence identifies 12th large earthquake on southern Hayward Fault
Scientists have identified a 12th large earthquake on the Hayward Fault at the Tyson Lagoon site near Fremont, California (north of San Jose) further defining the continuous historical record in the San Francisco Bay Area. The rapid recurrence rate, a large earthquake once every 160 years on average, makes the determination of earthquake recurrence from geological evidence of past large earthquakes especially critical to regional seismic hazard analysis.
The seismic record for southern Hayward Fault has been well documented. A review of all trench logs suggested the existence of an overlooked seismic event between two previously identified events, approximately 660 AD and 247 AD. The complete sequence of earthquakes, which now includes 11 paleoearthquakes since AD 92 prior to the last large earthquake in 1868, suggests considerable regularity of large earthquakes on the southern Hayward Fault.
Corresponding author: James J. Lienkaemper, U.S. Geological Survey, 650-329-5642,
jlienk@usgs.gov
"Evidence for a 12th Large Earthquake on the Southern Hayward Fault in the Past 1900 Years." Authors: James J. Lienkaemper of U.S. Geological Survey; Patrick L. Williams of San Diego State University; and Thomas P. Guildersen of Lawrence Livermore National Lab.
Santa Clara Valley's complex geology seen in varying ground motion
Underlying geological structures throughout the Bay Area result in important differences in ground motion during earthquakes. Santa Clara Valley serves as laboratory for studying the pattern of ground motion in sedimentary basins found around the world. This paper, authored by researchers at U.S. Geological Survey and the U.S. Bureau of Reclamation in Denver, looks at four sites in the Bay Area to understand how particular features, such the edges of a sedimentary basin, influence the propagation and amplification of seismic waves. This study shows how different wave propagation can occur in different areas of a single sediment-filled valley, reflecting the complexity of observed ground motion in the Bay Area.
The introduction of the San Jose portable seismic array of some 50 instruments in 1999 expanded the database of ground motion observations in the Santa Clara Valley. Each of the four sites studied presents different aspects of ground motion that are related to the underlying geologic structure: Blossom Hill, Cupertino and Evergreen basins in Santa Clara Valley, and a line perpendicular to the trace of the Hayward Fault.
Corresponding author: Stephen Hartzell, U.S. Geological Survey in Denver, 303-273-8572, shartzell@usgs.gov.
"Short Baseline Variations in Site Response and Wave Propagation Effects and Their Structural Causes: Four Examples in and around the Santa Clara Valley, California," by Stephen Hartzell, Leonardo Ramirez-Guzman, David Carver of U.S. Geological Survey in Denver; and Pengcheng Liu of U.S. Bureau of Reclamation in Denver.
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WASHINGTON, DC, October 5, 2010 — In a study of earnings inequality among white women, researchers at the University of Massachusetts Amherst find that having children reduces women's earnings, even among workers with comparable qualifications, experience, work hours and jobs. While women at all income levels suffer negative earnings consequences from having children, the lowest-paid women lose the most from motherhood. This earnings penalty ranges from 15 percent per child among low-wage workers to about 4 percent among the highly paid. The findings are published in the ...
JUPITER, FL, October 5, 2010 - Scripps Research Institute scientists have shown for the first time that the neurotransmitter serotonin uses a specialized signaling pathway to mediate biological functions that are distinct from the signaling pathways used by hallucinogenic substances. The new findings could have a profound effect on the development of new therapies for a number of disorders, including schizophrenia and depression.
The study was published in the October 6, 2010 issue of the Journal of Neuroscience.
Serotonin has tremendous influence over several brain ...
Chemists at Vanderbilt University have created a new class of liquid crystals with unique electrical properties that could improve the performance of digital displays used on everything from digital watches to flat panel televisions.
The achievement, which is the result of more than five years of effort, is described by Professor of Chemistry Piotr Kaszynski and graduate student Bryan Ringstrand in a pair of articles published online on Sept. 24 and Sept. 28 in the Journal of Materials Chemistry.
"We have created liquid crystals with an unprecedented electric ...
After a decade of joint work involving 2,700 researchers from 80 countries, the world's scientists – as well as the general public – can now access the Census of Marine Life, which provides the first in-depth look at the more than 120,000 diverse species which inhabit our oceans.
The Census of Marine Life initiative, started in 2000, is the result of one of the largest scientific collaborations ever conducted , the result of more than 540 expeditions and 9,000 days at sea, plus more than 2,600 academic papers published during that period.
The just-released census paints ...
Measuring a fuel cell's overall performance is relatively easy, but measuring its components individually as they work together is a challenge. That's because one of the best experimental techniques for investigating the details of an electrochemical device while it's operating is x-ray photoelectron spectroscopy (XPS). Traditional XPS works only in a vacuum, while fuel cells need gases under pressure to function.
Now a team of scientists from the University of Maryland, the U.S. Department of Energy's Sandia National Laboratories, and DOE's Lawrence Berkeley National ...
New neuroscience research by life scientists from UCLA and Australia may potentially help people who have lost their ability to remember due to brain injury or disease.
By examining how we learn and store memories, these scientists have shown that the way the brain first captures and encodes a situation or event is quite different from how it processes subsequent similar events.
The study is published in the Sept. 29 edition of the online journal PLoS ONE, a publication of the Public Library of Science.
Memories are formed in the part of the brain known as the ...
The following highlights summarize research papers that have been recently published in Geophysical Research Letters (GRL), Journal of Geophysical Research-Atmospheres (JGR-D), or Water Resources Research (WRR).
1. Antarctic sea ice increase not linked to ozone hole
While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simulations have indicated that the ozone hole induces ...
The oldest evidence of the dinosaur lineage—fossilized tracks—is described this week in Proceedings of the Royal Society B. Just one or two million years after the massive Permian-Triassic extinction, an animal smaller than a house cat walked across fine mud in what is now Poland. This fossilized trackway places the very closest relatives of dinosaurs on Earth about 250 million years ago—5 to 9 million years earlier than previously described fossilized skeletal material has indicated. The paper also described the 246-million-year-old Sphingopus footprints, the oldest evidence ...
CHAMPAIGN, Ill. – When the economy sours, small firms seeking credit tend to face higher costs of financing, leading them to reinvest their profits before they pay off creditors, according to research published by a University of Illinois finance expert.
Small firms, especially those considered financially constrained as a result of their size, low dividend payment or lack of bond rating, often become bogged down in debt because they "get hooked on cheap money, when they can find it" says U. of I. finance professor Murillo Campello.
"Since small firms are usually financially ...
AMES, Iowa - Some fisheries in the United States are poised to undergo major changes in the regulations used to protect fish stocks, and Iowa State University researchers have estimated that the new system will be an economic boon to the fishing industry.
Quinn Weninger and Rajesh Singh, both associate professors in economics, estimated harvesting costs under the old system and compared that to the newly proposed fishing regulations that lift many restrictions that cause inefficiency while still limiting amounts to be harvested.
Their analysis focused on the Pacific Groundfish ...
