Why was Indonesia's earthquake so devastating?

Indonesian authorities are struggling to deliver aid to thousands of people displaced by a deadly earthquake that struck Indonesia's main island of Java this week. Monday's earthquake shook the West Java province, killing at least 271 people, with at least 100 of them being children, the chief of the National Disaster Mitigation Agency said on Thursday.

A number of people remain trapped in houses buried by the mud, with around 1,000 search and rescue personnel looking for people using heavy equipment, sniffer dogs and life detectors at Cijedia village, one of the worst-hit areas, in West Java.

The 5.6 magnitude earthquake on Monday struck a highly populated area — some 2.5 million people live in the mountainous Cianjur district. More than 2000 people were injured and another 61,000 people were forced to evacuate to shelters, leaving many without adequate supplies since the quake blocked the roads needed to get aid to those affected. Some 56,000 houses were damaged, while 171 public facilities, including schools, were destroyed, the National Disaster Mitigation Agency said. While the magnitude of the earthquake itself would typically be expected to cause light damage, experts say proximity to fault lines, the shallowness of the quake and inadequate infrastructure that cannot withstand earthquakes all contributed to extensive damage.