An aftershock measuring 5.1 on the Richter scale jolted the Sipura Mantawai region in West Sumatra at 1:48 on Saturday morning, ANTARA reported. The local meteorology and geophysics agency (BMG) said the epicenter of the earthquake was located at 1.53 degrees southern latitude and 99.81 degrees eastern longitude at a depth of 10 km under the sea level, or some 77 km northeast of Sipura. The temblor occurred 49 minutes after an earlier one measuring 5.0 on the Richter scale at 00:06 after midnight at 1.59 degrees southern latitude and 99.81 degrees eastern longitude at a depth of 10 km under the sea level. BMG said, on Thursday, Aug 20, three earthquakes also rocked West Sumatra and North Sulawesi. The first earthquake measuring 5.1 on the Richter scale rocked West Sumatra at 12:25 on Thursday. Its epicenter was located 1.42 degrees southern latitude and 99.96 degrees eastern longitude at a depth of 39 km under the sea surface, 67 km southwest of Padang. Later at 7:12 p.m. local time, the second temblor measuring 5.7 on the Richter scale rocked North Sulawesi. The epicenter of the second quake was located 3.91 degrees northern latitude and 126.74 degrees eastern longitude at a depth of 10 km, 12 km from Melonguane. After that the third one, which was an aftershock measuring 5.0 on the Richter scale jolted West Sumatra at 7:34 p.m. local time at 1.48 degrees southern latitude and 99.79 degrees eastern longitude at a depth of 10 km under the sea surface, 82 km northeast of Sipura, in Mentawai. Indonesia is prone to seismic upheavals due to its location on the so-called Pacific "Ring of Fire", and an arc of volcanoes and fault lines encircling the Pacific Basin. At 9.05 am on Wednesday, another earthquake measuring 4.2 on the Richter scale jolted Yogyakarta. The epicenter of the earthquake was located at 8.4 degrees southern latitude and 110.45 degrees eastern longitude at a depth of 10 km under the sea surface, 28 kilometers southeast of Yogyakarta.
