Complex sentence: Simeulue, and the M8.4 September 2007 Mentawai earthquakes produced the largest release of elastic strain energy since the 1957/1964 series of shocks on the Aleautian/Alaska trench.
Split into simpler sentences: Simeulue, and the M8.4 September 2007 Mentawai earthquakes. This series of events produced the largest release of elastic strain energy since the 1957/1964 series of shocks on the Aleautian/Alaska trench.