Nav: Home

BSSA special issue on rotational seismology

April 27, 2009

SAN FRANCISCO, April 27, 2009 - A special May issue of the Bulletin of the Seismological Society of America (BSSA) focuses on the emerging field of rotational seismology and its applications to engineering. The special issue will feature seismological research on all aspects of rotational ground motions (including theory, instrumentation, observation, and interpretation) and on rotations in structural response.

Rotational seismology is of interest to a wide range of disciplines, including various branches of seismology, earthquake engineering, and geodesy, as well as to physicists using Earth-based observatories for detecting gravitational waves generated by astronomical sources as predicted by Einstein in 1916.

Seismology and earthquake engineering have been based on the observation and modeling of translational ground and structural motions. Although rotational effects from earthquakes have been observed for centuries, rotational ground motion has been ignored due to a widespread belief that rotation is insignificant and practical difficulties in measuring it. Theoretical work in modern rotational seismology began in the 1970s, and attempts to deduce rotational motion from accelerometer arrays began in the 1980s. However, modern direct measurements of rotational ground motions began only about a decade ago when affordable angular sensors became sensitive enough (capable of measuring an angle of less than ten thousandth of a degree) to detect rotations from small earthquakes, while large ring laser gyros (intended for studying the Earth's rotation) became capable of detecting even smaller rotations from distant earthquakes.

Ring laser observations at Wettzell, Germany and at Piñon Flat, California demonstrated consistent measurements of rotational ground motions in the far field. The high cost of present high-precision ring laser gyros (costing $1 million or more) makes widespread deployment unlikely. Less expensive and/or less sensitive alternatives are now being pursued by five academic groups. At present, only Taiwan has a modest program to monitor both translational and rotational ground motions from regional earthquakes at several free-field sites, as well as two arrays equipped with both accelerometers and rotational seismometers in a building and a nearby site.

Based on the developments described in the BSSA special issue, observation, analysis, and interpretations of both rotational and translational ground motions will soon play a significant role in seismology and earthquake engineering.
The lead guest editor William H. K. Lee is Scientist Emeritus at the U.S. Geological Survey in Menlo Park, California. He can be reached at

Seismological Society of America

Related Earthquakes Articles:

Stanford researchers explain earthquakes we can't feel
Researchers have explained mysterious slow-moving earthquakes known as slow slip events with the help of computer simulations.
Solved: How tides can trigger earthquakes
Some earthquakes along mid-ocean ridges are linked with low tides, but nobody could figure out why.
Cataloging Southern California's tiny hidden earthquakes
Nearly 1.8 million tiny tremblors have been added to the catalog of total seismic events in Southern California over the past decade, reports a new study, which details the most comprehensive earthquake catalog to date.
Measuring iceberg production with earthquakes
An international team led by French researchers from the CNRS and Paris Diderot University came up with the idea of using earthquakes generated when icebergs break away -- felt hundreds of kilometres off -- to measure this ice loss.
Injection wells can induce earthquakes miles away from the well
A study of earthquakes induced by injecting fluids deep underground has revealed surprising patterns, suggesting that current recommendations for hydraulic fracturing, wastewater disposal, and geothermal wells may need to be revised.
More Earthquakes News and Earthquakes Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...