Rapid Determination of Earthquake Magnitude Using Measurements of the Dominant Period of P-Waves Observed at Local Stations in North Sulawesi

摘要

This research aims to examine basic physics principles and mechanisms of determining local earthquake magnitude Mpd observed at local seismic stations in North Sulawesi and its surroundings using rapid calculations of the dominant period from P-waveforms with the help of JokoTingkir,a package program used for this issue. The data used were secondary, downloaded from Webdc3 in the form of magnitudes scaled with MW in North Sulawesi during 2010–2015 with all events were sea-hypocentered. The study focuses on estimates of a local earthquake size as a primary parameterin seismic studies and surveillance via a linear equation relating the dominant period Td to the earthquake size MW. When this equation was inverted an empirical formula was then obtained, Mpd = (Td + 7.7536)/1.7018 for North Sulawesi and its nearby regions. The formula was used to recalculateevents having small to moderate magnitudes that occurred in the region of interest from 2010 to 2015. The results were then compared to those of reference MWCMT provided by the Global CMT catalog with a standard deviation of the scatter of only 0.2 was found, in very good agreement with previouswork. We conclude that there is no significant difference in magnitude between values derived from the method proposed in the present study and those given by the Global CMT catalog for the reference of magnitude. The results are discussed in terms of rapidness and accuracy of earthquake magnitudedetermination required for use of hazard mitigation.