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Tag: geologists

Geologists locate source of chemical signature in ancient volcanic rocks

Geologists locate source of chemical signature in ancient volcanic rocks

Science
Oct. 28 (UPI) -- Geologists have linked ancient volcanic activity with a unique geochemical signature measured in rock samples recovered from the coast of Greece. According to a new study published this week in the journal Nature Geoscience, an ancient ring of explosive arc volcanoes, which erupted some 45 million years ago, accounts for the highly oxidized rocks found along the coast of Greece. Researchers hypothesized that fluids from subducted oceanic rocks can explain the oxidation found in rocks formed by the arc volcanoes. To test their hypothesis, scientists went looking for the fluid source's geochemical signature in ancient subducted oceanic crust located on the Greek island of Sifnos. Oxidizing fluids influence the iron isotope composition found large garnet crystals, and becau...
Geologists use tide gauge measurements to track tremors

Geologists use tide gauge measurements to track tremors

Science
Feb. 15 (UPI) -- Geologists have developed a method to track tremors using water level measurements recorded by tide gauges. Today, scientists use GPS to track the elevation changes caused by episodic tremors and slow slip earthquakes, but the Global Positioning System has only been in operation since 1995. Researchers have been tracking water levels for much longer. The new analysis technique -- detailed this week in the journal Bulletin of the Seismological Society of America -- could allow researchers to probe pre-GPS tide gauge data for unique seismic patterns called episodic tremor and slip events, or ETS. "The part of the fault that is slipping during [an episodic tremor and slip] can't be totally locked, because it is experiencing periodic slow earthquakes, so that area sort of def...
Rivers can cause earthquakes, geologists claim

Rivers can cause earthquakes, geologists claim

Science
Dec. 21 (UPI) -- New research suggests river erosions can explain the pattern of earthquakes faraway from plate boundaries, like the 4.4 magnitude quake that shook Eastern Tennessee last week. Geologists Ryan Thigpen and Sean Gallen designed a model to simulate how the removal of 500 feet of rock influences crust behavior in the Tennessee Valley. The model's results match the pattern of earthquakes in the region over the last century. "We're taught in introductory geology that the vast majority of earthquakes occur at plate tectonic boundaries, such as in Japan and along the San Andreas fault zone," Thigpen, an assistant professor at the University of Kentucky, said in a news release. But the traditional earthquake mechanisms can't explain the rumbles among seismic zones of East Tennessee...