Abstract:
Three purposes are set for this study: first, to discover the statistical properties of total (labeled plus unlabeled) earthquakes in Taiwan; second, to find out the regression equations of intensity and relationship to its magnitudes (ML), depth (km) of hypocenters, and location (longitude and latitude); third, to plot three-dimensional graphs of magnitudes (ML), depth (km), and intensity (gal) for all 9,871 earthquakes occurring from January 1995 to June 2107. All earthquakes recorded are obtained from the seismic archive of the Central Weather Bureau (CWB) of Taiwan. The statistical earthquakes properties evaluated in this paper include: yearly numbers, mean times per month, mean times per year, mean depth (km), mean magnitude (ML), maximum magnitude, interval of time between two earthquakes, energy released ratio, and energy equivalent to the number of atomic bombs. Hualien, a county in the east of Taiwan, is the place with the highest frequency of earthquakes, the shortest interval between two earthquakes, and the strongest released energy. The energy released from total earthquakes in Hualien in the period of January 1995 to June 2017is equivalent to 185.1 atomic bombs which were dropped in Hiroshima at the end of World War II. Totally 5.04E+23 ergs of energy are accumulated by all 9,871 earthquakes in Taiwan for the past 22.5 years. Such an energy is equivalent to 800.31atomic bombs. To express an astronomical number of energy with atomic bomb numbers in each city and county substantiates abstract energy into graphical reality. Most of the earthquakes in Taiwan's twenty municipal areas are categorized to be shallow (<70km), except Keelung, which has an average depth of hypocenters at 114.92km (intermediate-depth). Maybe it is because the hypocenters of Keelung are in the submerged tectonic plate. In the past 270months (January 1995 to June 2017) the strongest magnitude (Richter magnitude scale, ML) was 7.3. Although Taitung also recorded the same magnitude, its epicenter is off-island. Therefore, no major damage and injury has been filed.
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