A seismological research team from the University of Nevada, Reno is finding ways to make precariously balanced rocks talk. In so doing, they are unlocking valuable scientific information in assessing seismic hazards in areas throughout the West.
"There's really no long-term data to test seismic hazards other than precarious rocks," said Matthew Purvance, a postdoctoral scholar in geophysics at the University, who authored the article along with James Brune, professor in the Department of Geological Sciences and past director of the Nevada Seismological Laboratory, and Rasool Anooshehpoor, research professor in the Nevada Seismological Laboratory.
"By studying precariously balanced rocks, it can serve as an indicator that an earthquake of a sufficient size to topple a tippy rock has not occurred … at least for a very long time. We think this is a fundamental story that gives fundamental information on seismic hazards that has never been done before."
The data from the study is important, as it not only tests ground-motion probability, but can help further refine United States Geological Survey hazard methodologies that are used by engineers to formulate building codes. Purvance explained that seismologists and engineers since the late 1960s have increasingly followed a method known as probabilistic seismic-hazard analysis in trying to get a more firm grasp on earthquake probability. This analysis allows researchers to determine the number and magnitude of earthquakes on relevant faults. The study of precarious rocks, which act as "witnesses" to strong seismic events throughout history, has provided scientists an important research window to test the predictions of probability, Purvance said.
The team tested massive rocks of up to 1,000 pounds and more than 10,000 years old, measuring the force and angle it would take to tip them over. One of the more interesting aspects of the study was a technique used by Anooshehpoor, which measured the restoring force that has allowed the rock to remain upright through centuries of wear and the force of past strong seismic events.
Anooshehpoor's technique allowed the team to measure a tipping boulder's restoring force with a digital load cell and the rock's tilt with an inclineometer. The work wasn't easy. By pushing and pulling on the massive, bus-sized rocks with a series of wire cables, nylon straps, chains, pulleys, winches, hydraulic pistons, ground anchors and 4 by 4 blocks of wood, the team was able to record data for precarious rocks that had never been tested before.
"It gives us very useful information about the precarious rocks and further adds to the knowledge of gauging earthquake hazards," Purvance said, noting that it was work by Brune in the early 1990s with precarious rocks in southern California that led to the rocks becoming more widely recognized as an accurate barometer of seismic force and occurrence. "These measurements help better explain the story of how the rock has managed to withstand some of the forces of time and nature."
Added Anooshehpoor: "The rocks that we have studied are from large earthquakes and are so rare. If throughout history the world had tons of instruments and recorded many of these earthquakes, we probably wouldn't have the need to study precarious rocks. The lack of data has been a major problem in estimating ground motion. With this study, we've been provided with another opportunity to give the engineers the right information they need."
John Trent | EurekAlert!
Heidelberg Researchers Study Unique Underwater Stalactites
24.11.2017 | Universität Heidelberg
Lightning, with a chance of antimatter
24.11.2017 | Kyoto University
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences