Temblors' cause revealed

SANDPOINT — The earthquake that shook the Sandpoint area in April was not your typical earthquake, a University of Idaho researcher has uncovered.

Geology graduate student Daisuke Kobayashi researched the earthquake and found it was caused by the Earth's crust mashing together. A typical earthquake is caused when the crust pulls apart.

Kobayashi said the activity could signal the awakening of a dormant fault. He presented his work at American Geophysical Union meeting this week and recommended more seismic monitoring in the Idaho Panhandle.

The research looked into a series of small earthquakes that shook the area this past year, which also included one of a 3.4-magnitude rumbled the Sandpoint area Nov. 23.

More than 98 people reported felt the earthquake in 14 ZIP codes, all in North Idaho.

According to the U.S. Geological Service, the quake was felt all around Lake Pend Oreille.

The intensity of the quake reached a three, or “weak shaking,” Paul Bodin, research professor at the University of Washington, said in November.

Usually damages occur around earthquakes reaching a six intensity.

The earthquake was at a depth of 18 and a half kilometers, or about 10-12 miles deep into the ground, he said.

Bodin said there have been earthquakes more frequently in North Idaho recently, but that is because the area is known for seismic activity and he sees nothing unusual or surprising with any of the recent earthquakes.

Information: https://eos.org/articles/the-backwards-earthquakes