A major undersea earthquake struck the Celebes Sea off the coast of Sulawesi just after 6 o’clock this morning, New Zealand time. A tsunami warning was issued for coastlines within a thousand kilometres of the quake, but it was considered that a threat to Pacific coastlines did not exist.
The magnitude 7.5 earthquake, which struck at 6:03 a.m. New Zealand Daylight Time on Monday the 17th of November 2008, was located 135 km north-west of Gorontalo, Sulawesi (305 km west of Manado, Sulawesi) at a depth of 21 km. The epicentre was 1485 km south of the Philippines capital, Manila, and 1890 km east-north-east of the Indonesian capital, Jakarta.
The strength, undersea location and shallowness of the quake prompted a tsunami warning from the Pacific Tsunami Warning Centre (PTWC). In a bulletin issued at 6:13 a.m. NZDT, the PTWC described the quake as magnitude 7.6 at a depth of 40 km. It considered that there was no threat to coastlines in the Pacific, however it was considered that coasts within a thousand kilometres of the epicentre could be in danger. The PTWC recommended that regional authorities nearby should take immediate action to evacuate coastal areas.
Two shallow aftershocks of 5th magnitude have been reported by the U.S. Geological Survey. A magnitude 5.6 quake struck at 6:35 a.m. and a magnitude 5.5 event at 7:20 a.m.
[Compiled from data supplied by the U.S. Geological Survey and its contributing agencies; and the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre.]