A recent study of major earthquakes since 1992 – the kind that can generate widespread damage – revealed that such events routinely trigger smaller jolts around the planet, including areas that are not prone to quakes.
One example was the 1992 Landers earthquake that was a magnitude 7.3 and shook up the Southern California desert. The surprise was that it caused small jolts as far away as Yellowstone National Park – some 800 miles away.
“Earthquakes have been thought of to be very isolated events,” Aaron Velasco, lead author of the study and University of Texas at El Paso associate professor of geological sciences, said. “Now we’re seeing a relationship between big earthquakes and smaller events around the world.”
Velasco and Stephen Hernandez, a UTEP undergraduate student, analyzed 15 major earthquakes stronger than magnitude 7, and found that at least 12 of them triggered small quakes hundreds and even thousands of miles away.
The pair was joined on the study by seismologists Kris Pankow of the University of Utah and Tom Parsons of the U.S. Geological Survey in Menlo Park, Calif. The team’s analysis was published online Sunday, May 25, 2008, in the journal, Nature Geoscience.
The team analyzed data from more than 500 seismic recording stations five hours before and five hours after earthquakes that registered more than 7 on the “moment magnitude” scale, which scientists say is the most accurate scale for large earthquakes.
The data was obtained from the Incorporated Research Institutions for Seismology, a consortium of universities, from 1992 through 2006. It included the Landers quake, the magnitude 7.9 Denali fault quake in Alaska in 2002, and the magnitude 9 Sumatra-Andaman Islands quake near Indonesia in 2004. That last quake generated a catastrophic tsunami that washed out villages and was responsible for many of the quake’s 227,898 deaths in 11 countries that share a coastline with the Indian Ocean.
Scientists previously noted that those three major quakes triggered not only nearby aftershocks, but small quakes at great distances. In the case of the 2004 quake, there is evidence that it produced temblors in Ecuador half a world away.
“This phenomenon has been documented for several isolated events in certain regions, but now we’re able to show that this is occurring everywhere,” Velasco said. “As a result, our ideas about how earthquakes occur and how we react have to change.”
The U.S. Geological Survey and the National Science Foundation funded the study.
Kimberly Miller | newswise
Hidden river once flowed beneath Antarctic ice
22.08.2017 | Rice University
Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter
17.08.2017 | Swansea University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences