The tremor, the strongest to hit western Montana since 1959, struck at 12:30 am local time, startling many people as they slept. The quake struck in an area with a fault known as the Lewis and Clark line, a zone that extends for about 250 miles (400 kilometers) from northern Idaho to east of Helena, Montana. The USGS said the tremor was followed by a series of aftershocks, two of which measured 3.9 and 4.4. The largest quake on record in western Montana struck in August 1959 and measured 7.2. The so-called Hebgen Lake quake triggered a major landslide that killed 28 people and caused significant damage.

Source: The Nation Bangkok July 06, 2017 20:48 UTC