Indonesia is obviously seating on a tectonic plate. I believe a similar earthquake ravaged the country, was it last year or so; now another earthquake even 4th in just a day.
“5.7 Magnitude Earthquake Hits Sea Off Indonesia, Fourth Quake In One Day - SaharaReporters.com”
“5.7 Magnitude Earthquake Hits Sea Off Indonesia, Fourth Quake In One Day - SaharaReporters.com”