Timeline. The first earthquake occurred at 11:10:26 UTC (18:10 local time) on 12 September 2007, and was an 8.4 M w earthquake on the moment magnitude scale.It was centered about 34 km underground, at , about 130 km southwest of Bengkulu on the southwest coast of Sumatra, Indonesia, and some 600 km west-northwest of Indonesia's capital city, JakartaIt was followed …