A damaging earthquake struck early Monday in northwestern China, leaving dozens dead, according to news reports.

Local authorities said at least 75 people were killed and more than 500 injured as homes and buildings crumbled, Xinhua reported. The death toll is likely to climb as rescuers are still searching for missing people.

The earthquake had a preliminary magnitude of 5.9 and was centered in south-central Gansu Province, 8 miles (13 km) east of the city of Chabu, according to the U.S. Geological Survey (USGS). It originated 6.1 miles (9.8 km) deep and struck at 7:45 a.m. local time (UTC) 2345, the USGS reports.

China's earthquake monitoring service, meanwhile, measured the quake as 6.6 in magnitude, and local authorities said more than 300 aftershocks had been recorded in the region, the strongest measuring magnitude 5.6, according to Xinhua.

The USGS says the area around the Himalayas is "one of the most seismically hazardous regions on Earth." Frequent earthquakes are generated by continental collision of the Indian tectonic plate and the Eurasian plate.

Earthquakes of the size of the one struck today can cause significant damage in areas with outdated building standards. But the damage caused by any single event depends on the quake's depth, proximity to populated areas, building standards in the region, as well as the type of earthquake. The USGS frequently updates the magnitude of an event after more data is analyzed.

An earthquake's magnitude is a measure of the energy released at the source. It is just one predictor of the shaking that may ensue, which is affected by local and regional geology. Scientists know in a general sense what causes Earthquakes but are unable to predict specific quakes.

This article will be updated if significant additional information becomes available. Find more earthquake news here.