Nepal Earthquake Strikes One of Earth's Most Quake-Prone AreasMagnitude 7.8 temblor comes in a region with a long geologic history of big earthquakes.

 People search for survivors in a collapsed building in Kathmandu on April 25 after a magnitude 7.8 earthquake.

PHOTOGRAPH BY NARENDRA SHRESTHA, EPA

By Brian Clark Howard, National Geographic 

PUBLISHED APRIL 25, 2015A strong, magnitude 7.8 earthquake  rocked Nepal early Saturday, destroying buildings, damaging historic temples, and killing hundreds. As search and rescue efforts continue through the day, scientists explore the powerful geologic forces that caused the disaster.

The earthquake was centered 48 miles (77 kilometers) northwest of Nepal’s capital of Kathmandu, a city of 1 million. At least 2,300 people have been declared dead, mostly in Nepal, with additional victims in India and China. There are more than 4,600 injured in Nepal and the death toll is expected to rise as people presumed trapped in collapsed structures are found.Avalanches were also reported on Mount Everest as a result of the shaking, sending climbers running and reportedly killing at least 18   at base camp.

After the main quake, some 14 aftershocks were felt by local people. Some were strong enough to cause more damage, up to a magnitude 6.6, reports the UN Office for the Coordination of Humanitarian Affairs .

The earthquake struck at 11:41 a.m. local time (05:51 GMT) at an estimated depth of 9.3 miles (15 kilometers), which is considered shallow and therefore more damaging than quakes that originate deeper in the ground.

The region has a long geologic history of big earthquakes, reports the U.S. Geological Survey (USGS), although they have been relatively rare in modern times. Just four events of magnitude 6 or larger have been reported over the past century.

The temblor was caused by a sudden thrust, or release of built-up tension, along the major fault line where the plate carrying India is slowly diving underneath the one carrying much of Europe and Asia, according to the USGS .

The area is "one of the most seismically hazardous regions on Earth,” reports the survey.  

The two massive plates are colliding at a rate of about 1.7 inches (45 millimeters) a year, pushing up the Himalaya mountain range in the process. But due to friction along the plate boundaries, the sliding is not smooth or even. Some of the rocks stick, causing pressure to build. When the rocks finally give way under the strain, the plates jerk rapidly, releasing the energy that causes an earthquake. (Learn more about how earthquakes form .)

In the area, a magnitude 6.9 earthquake in August 1988 killed nearly 1,500 people. An 8.0 event in 1934 severely damaged Kathmandu, killing 10,600. The largest quake in the region measured by instruments was a magnitude 8.6 event in 1950, centered in Assam in eastern India.

Both shallow and deep earthquakes have been observed in the region, thanks to its high level of geologic activity.