For many years, John Anderson, director of the Nevada Seismological Laboratory at the University of Nevada, Reno, has been telling citizens, reporters and other scientists from throughout the world that in terms of seismic activity in the 50 states, Nevada ranked as the third most active.
Then, during a meeting of the Nevada Earthquake Safety Council earlier this year, he learned that the United States Geological Survey (USGS) website actually ranked Nevada fourth, behind third-place Hawaii.
"One of the Safety Council members said, 'John, what in the world is going on here?'" Anderson remembered.
His curiosity piqued, Anderson began a study along with Yuichiro Miyata of the Nevada Seismological Laboratory to take another look at the data. The project turned into a national study, and their lists of the top 10 most seismically active states have just been published in the November/December issue of Seismological Research Letters, a bimonthly publication of the Seismological Society of America.
The undisputed leader for numbers of earthquakes? Alaska, of course, with California solidly in second place. But beyond that point, depending on how you measure activity, the rankings change. On the list that Anderson likes the best, which gives the greatest magnitude that is reached once per year on average, Nevada inches into third, at 5.1. For fourth-place Hawaii, it's 5.0.
The top 10 rankings, based on the magnitude of earthquake that occurs once per year on average: 1, Alaska, 6.70; 2, California, 6.02; 3, Nevada, 5.11; 4, Hawaii, 5.00; 5, Washington, 4.97; 6, Wyoming, 4.67; 7, Idaho, 4.57; 8, Montana, 4.47; 9, Utah, 4.29; 10, Oregon, 4.24.
"Everybody is dedicated to accurately portraying how and when earthquakes occur," said Anderson, who, as director of one of the nation's premier seismological laboratories, monitors such events on a daily basis. "The reason for talking about this is not to change the rankings or to have one state move ahead of another – it's to motivate people to build structures that resist earthquakes. If you're on this top-10 list, hopefully it will motivate you to be better prepared in the event of a large earthquake."
The lab, part of the University's College of Science and Mackay School of Earth Sciences and Engineering, records earthquakes in Nevada and parts of eastern California, as part of the U.S. Geological Survey's Advanced National Seismic System (ANSS). It also operates a seismic network in southern Nevada for the U.S. Department of Energy.
To determine the rankings, Anderson and Miyata consulted the ANSS catalog of earthquakes, which contains earthquake data from 1898 to 2005. They then supplemented this catalog with data from the USGS catalog of significant U.S. earthquakes from 1568-1989.
Miyata's participation as a GIS expert was also key, Anderson said.
"Yui is a GIS expert, and a graduate of our Department of Geography," Anderson said. "With GIS, it's very easy to sort out how many earthquakes have occurred with each state's borders."
"It only took a couple of days," Miyata said. "First, we took the whole earthquake catalog and divided it by state. And, we made sure that with states with coast line, we extended the borders to go about 100 kilometers (about 62 miles) beyond the coast."
In this way, the study was able to take into account seismic "hot spots" that exist undersea, and underneath, a state such as Hawaii.
Many earthquakes, including the magnitude-6.7 event that occurred in Hawaii recently, causing upwards of $50 million in damage, are driven by stresses set up on the flanks of active volcanoes by accumulated magma intrusions. Due to this concentrated volcanic source, Hawaii has a large number of smaller earthquakes. Seismicity in top-ranking states of Alaska, California and Nevada, however, is driven by plate tectonics, Anderson said.
For those keeping score, the difference in seismic activity between Nevada and Hawaii is not great, Anderson added.
"In terms of magnitude-7 earthquakes, Nevada and Hawaii are essentially tied, but in terms of magnitude-5 and greater earthquakes, Nevada is ahead," Anderson said. "Then, counting magnitude-3.5 and greater, Hawaii again leads. Considering the uncertainties, Nevada and Hawaii are essentially tied."
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