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Can the ground open up during an earthquake?
Shallow crevasses can form during earthquake-induced landslides, lateral spreads, or from other types of ground failures, but faults do not open up during an earthquake. An earthquake occurs when two blocks of the earth’s crust slide past one another after having been stuck together in one place for a long time, because of fiction on the fault, while the rest of the crust away from the edges has been slowly moving. If a fault could open up, no earthquake would occur in the first place because there would be no friction locking the two blocks together.
Why are we having so many earthquakes? Has naturally occurring earthquake activity been increasing? Does this mean a big one is going to hit? OR We haven't had any earthquakes in a long time; does this mean that the pressure is building up for a big one?
At 12:32 am Alaska time on January 23, 2018, a magnitude 7.9 earthquake shook Alaska residents out of their beds and set off fears of a tsunami all down the West Coast. Fortunately, the tsunami was only a few inches in height, but within an hour of the earthquake in Alaska, waves of a different sort were hitting far away in Florida.
The coastal geology of Simeonof Island, the southeastern-most island in the Shumagin archipelago of the Aleutian Islands, suggests the region has not experienced a great megathrust earthquake in at least the past 3,400 years.
Scientists from the U.S. Geological Survey (USGS) and their partners studying the largest on-land earthquake in North America in almost 150 years report new information that will help further safety-planning efforts for future large quakes, according to an article published in the May 16, 2003, edition of the journal Science.
Two faults (located on either side of project geologist Chris Fridrich) cutting Pleistocene fluvial gravels on the northern edge of the Poncha mountain block. These and other young faults exposed in area help reveal the latest kinematic (movement) and paleostress histories of the mountain block.
Fresh surface fractures (black arrows) along Brawley Fault Zone and across Ralph Road in response to the 2010 El Mayor-Cucapah earthquake; view to the north. Slight vertical component of slip (2 mm, up on east [right] side) more noticeable at white arrow.
Peter Haeussler prepares to measure the offset of a crevasse on the Canwell Glacier.
View southeast along the Totschunda fault.
At pass west of Delta River. Here there was roughly 5 m of offset. Note the push up in the background. There is permafrost at the bottom of the cracks.
The fault is clearly expressed through this pasture at N40 41.959', E030 30.196'. Offset of a small road is 2.4 m (a maximum).