JAKARTA, Indonesia- A powerful series of earthquakes shook northeastern Indonesia Thursday, injuring at least 11 people and damaging a number of homes and other buildings, officials said.

Setting off the chain of temblors was a magnitude 7.2 quake at 1:35 a.m. (12:35 p.m. ET Wednesday), the U.S. Geological Survey reported. The major quake was followed by no less than 18 aftershocks of magnitude 5.0 or higher over the next 13 hours. The number is nearly 30 when smaller aftershocks are counted.
The quakes were all clustered off the northeastern tip of Sulawesi Island, about 1,550 miles (2,495 km) east-northeast of Jakarta, where three major tectonic plates come together, according to Indonesia's Meteorological and Geophysics Agency. The plates massive, sometimes continent-sized, slabs of rock floating on the Earth's surface collide with each other, causing earthquakes.
Indonesia is located on the "Ring of Fire," an arc of volcanoes and fault lines encircling the Pacific Basin that is prone to frequent earthquakes and volcanic eruptions.
The full extent of damage was not immediately known as people fled from coastal areas to the surrounding hills for safety in the event of a tidal surge, said Priyadi Kardono, an official with the National Disaster Coordinating Agency.
Source: CNN