A preliminary report on seismicity declustering methods and completeness magnitude in eastern Sunda Arc

Data declustering separates mainshocks from both foreshocks and aftershocks while a reliable estimate of completeness magnitude is key point in seismic parameter determination. These play role seismicity-related work. In this preliminary study, we reported seismicity two Indonesian provinces, namely NTB NTT, as part eastern Sunda Arc using the USGS catalogue during 1970-2021 based on performance three methods (Gardner Knopoff, Reasenberg, Uhrhammer). were tested along with techniques M c determination (MAXC, EMR, BC) provided by ZMAP to minimum cut-offs, leading an accurate magnitude. After careful examination, Reasenberg BC proved be suitable for characterising regions interest, where was calculated under linear assumption cumulative frequency-magnitude distribution (FMD), widely known Gutenberg-Richter law. The results revealed that b parameters are influenced choice specific algorithm calculation . NTT found have higher level than rates southern provinces those northern part. However, number strong ground motion w ≥ 6.5 area larger southern, indicating potency Flores Back-arc Thrust generating large earthquakes hence possible tsunamis.