Fig. 1

(Upper) Broadband seismic observation networks, and (lower) estimated CMTs of detected earthquakes by the SWIFT system in the regions of a Indonesia and the Philippines, and b Chile. Red squares indicate the broadband seismic stations currently used by SWIFT: 133 stations in a and 48 stations in b. A total of 1488 CMTs of M w 4.3–8.6 throughout Indonesia and the Philippines were obtained from June 25, 2007, to December 31, 2015, and 220 CMTs of M w 4.0–8.2 throughout Chile were obtained from April 24, 2014, to December 31, 2015. Dashed curves indicate plate boundaries derived from Bird (2003)