A magnitude 7.5 Earthquake shook the Hindu Kush region of Afghanistan yesterday. The epicenter was located about 254 km (158 mi) northeast of Kabul. The shaking started at 5:09 EST and was the result of movement along a reverse fault at intermediate depths, of 212.5 km (132.1 mi). Earthquake depths are categorized as shallow (up to 70 km), intermediate (up to 300 km) and deep (greater than 300 km), and generally the deeper the Earthquake the less severe the surface shaking. The depth of this event likely limited the shaking from such a powerful quake, that unfortunately has been responsible for at least 250 deaths in Afghanistan and Pakistan.
This event occurred on a nearly vertical reverse fault that is the result of convergence of the Indian tectonic plate with the Eurasian tectonic plate. The Indian plate is moving at an astounding 37 mm/yr northward into the Eurasian plate. This convergence is also responsible for the mountain building, including the Himalayan, Karakoram, Pamir and Hindu Kush ranges, and makes the terrain in this region of the world so rugged and inaccessible.
This region has experienced recent quakes in 2002 with a magnitude 7.4 located only 20 km to west of this event, and a 2005 magnitude 7.6 Earthquake that devasted the Kashmir region that killed over 75,000 people.
Summary of Earthquake event from the USGS: http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2015/20151026.pdf