After a 5.7 earthquake, Utah seismologists investigate a ‘virtually unknown’ fault

Soon after Salt Lake City stopped shaking March 18 from its strongest earthquake on record, Amir Allam, a University of Utah seismologist, knew he had to get busy if he hoped to closely study the hundreds of aftershocks he knew would follow the 7:09 a.m. jolt.The fault that is believed to have moved along the eastern base of the Oquirrh Mountains is virtually unknown, and here was a chance, dropping out of the blue, to image it.But Allam had a problem.All 210 of the U.’s portable seismogra