Tag Archives: seismic
Seismic unrest: New earthquake swarm starts on La Palma, Spain – Over 300 quakes hit mid-Atlantic Azores Islands, Portugal – Are volcanoes waking up there?
Seismic unrest is being reported since last Saturday, February 10, 2018 with a new earthquake swarm starting in the southeast of the island of La Palma in Spain. Now, on February 12, 2018 more than 300 small earthquakes have rattled the mid-Atlantic Azores Islands overnight.
Seismic unrest continues at Bogoslof volcano. Scientists are watching the eruption around the clock — even though monitoring stations are far from the site.
Chris Waythomas, of the U.S. Geological Survey, is observing a particular indication of increased seismic activity: volcanic tremors.
“You can think of it as the sort of signal you might get if you were to seismically monitor an organ pipe,” Waythomas said. “As air moves through the pipe, it resonates. When it impinges on the pipe, it produces motion and that’s what we’re kind of measuring.”
Waythomas said the problem is there’s a lot of wind and that can obscure the signal.
“It looked to us like there was increase in this tremor signal,” Waythomas said. “We wanted to alert everyone it was possible this could be accompanied by a large steam or ash emission.”
The Alaska Volcano Observatory also has access to satellites which they use to look for steam or ash plumes and thermal signals, but cloud cover is making it difficult to confirm.
Bogslof volcano began erupting last week.
In Southern California, scientists listening to rumblings deep underground found seismic activity at deeper-than-expected levels, and it may signal new earthquake extremes, according to a new study.
Deeper or smaller seismic activity can be very difficult to monitor, especially in urban areas, due to the distance between seismicity monitors and the noise caused by traffic and industry. In order to better see these so-called micro signals, a group of researchers temporarily deployed detectors along the Newport-Inglewood fault (NIF), which stretches nearly 50 miles (80 kilometers), from Culver City to Newport Beach, in Southern California.
“It’s very helpful for us to do these kinds of studies where the seismic risk is high because of the dense concentrations of population,” study lead author Asaf Inbal, a geophysics graduate student at the California Institute of Technology, told Live Science. “Most of the damage is inflicted by large earthquakes, but these small earthquakes like the ones we observe at NIF occur much more frequently, and their location can be used to highlight active faults and their depth.”
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