 The Indonesian Meteorological, Climatological, and Geophysical Agency assigned a magnitude of 6.8, and the United States Geological Survey (USGS) reported a similar value of 6.1 (both body wave magnitude) that were calculated from short-period seismic waves (1–2 seconds in the case of the USGS).The USGS then presented a moment magnitude of 7.2 that was calculated from 5–100-second surface waves, and Harvard University subsequently revealed that a moment magnitude of 7.7 had been resolved based on even longer 150-second surface waves.In tsunami prone regions, strong earthquakes serve as familiar warnings, and this is especially true for earthquakes in Indonesia.