A new report provides confirmation that the science of seismicity, and the theories of geologists are in a constant state of flux……. just like the planet Earth, things always changing (as we learn / understand more about these natural processes).
New studies show recent large Earthquakes lead to seiesmic activity in regions far away from the earthquake epicenter.
Ironically, last night, I made a full earthquake post which touches upon the NEW science of RELATED earthquakes across vast distances. Up until we online researchers started to notice the relation of earthquakes ‘bouncing’ back and forth across entire continents within a few hours of each other, seismologists / geologists said this could not happen!
Scientists used to say (up until currently) one earthquake does not lead to another earthquake elsewhere.
This outdated incorrect theory , held by most professionals, is now proved false.
“Antarctica’s ice snapped and popped because of a major earthquake in Maule, Chile, halfway around the world, a new study reports.
Antarctica has been touched by great earthquakes before. In March 2011, Japan’s Tohoku tsunami tore off two Manhattan-size icebergs from the Sulzberger Ice Shelf, more than 8,000 miles (13,000 kilometers) south. Sailors also reported a massive Antarctica iceberg-calving event after Chile’s 1868 great earthquake.
But this is the first evidence that distant earthquakes can trigger icequakes in Antarctica. Icequakes are seismic tremblings caused by sudden movement within a glacier or ice sheet, such as from a fracturing crevasse. (Anyone who has dropped an ice cube into a glass of water knows ice snaps under stress.) [Listen to Antarctica’s Icequakes]
A little crack
Chile’s magnitude-8.8 earthquake on Feb. 27, 2010, set off a flurry of Antarctic icequakes, each lasting from one to 10 seconds, researchers report today (Aug. 10) in the journal Nature Geoscience. The epicenter was 2,900 miles (4,700 km) north of Antarctica.
“Regular icequakes probably occur all the time in Antarctica and other polar regions,” said lead study author Zhigang Peng, a seismologist at the Georgia Institute of Technology in Atlanta. “What we found is that they occurred more during the seismic waves of the Maule event.”
Only 12 of Antarctica’s 42 seismometers picked up icequakes after the Maule earthquake, but the signals seemed to fit a pattern. The pattern suggests that opening or closing of shallow crevasses generated the tiny tremors. For example, seismic stations near Antarctica’s mountain ranges and fast-flowing ice rivers known as ice streams were more likely to see icequakes. These are areas with a lot of crevasses. The high-frequency shaking also fits with cracking of brittle ice. [Album: Stunning Photos of Antarctic Ice]
“We think the crevasses are being activated by the surface waves from this big earthquake coming through, and that’s making the icequake,” said study co-author Jacob Walter, a research scientist at the University of Texas Institute for Geophysics in Austin.
There are also intriguing hints that only crevasses properly aligned toward the incoming seismic surface waves were pinched closed or jacked open, setting off icequakes. However, the evidence is too sparse to test the idea at this time, Walter said.
“For fault zones and tectonic earthquakes, there is a dependence on which direction the wave came from,” Walter told Live Science. “We’re continuing to work on understanding the phenomenon.”