Analisis Spektral Dan Penentuan Hiposenter Gempa Gunung Lewotobi Dan Egon Serta Kondisi Seismotektonik Daerah Sekitarnya

Abstract

Has done research on spectral analysis and determination of hypocenter Lewotobi and Egon and its relation to tectonic earthquakes in the surrounding area. The puporse of the research was to determine the spectral characteristics, hypocenter, b-value, as well as investigating the relationship between volcanic earthquake and tectonic earthquake that occurred in the area around. The data of volcanic seismicity obtained from the Lewotobi and Egon PGA Post on January 1st until January 31st 2016. And the data of tectonic seismicity obtained from International Seismicity Center (ISC) catalog and U.S. Geological Survey National Earthquake Information Center (USGS/NEIC) on 1965-2016. Spectral analysis of earthquake that recorded on a seismograph in PGA post used to get dominant frequency, the deep volcanic earthquake, shallow volcanic earthquake, and local tectonic on Lewotobi used to determine hypocenter of earthquake of Lewotobi mount. For the data of tectonic earthquake obtained by doing analysis b-value. The results show that dominant frequency each earthquake that occurred on Lewotobi: deep volcanic earthquake 10-13 Hz, shallow volcanic 4,87-13,6 Hz, tornillo 1,69-16,8 Hz, harmonic tremor 1,72-2 Hz, far tectonic 1,041-5,282 Hz, local tectonic 1,80-2,79 Hz, blowing 2,54-7,53 Hz, low frequency 0,72-1,97 Hz. For earthquake on Egon: deep volcanic earthquake 10-13,0 Hz, shallow volcanic 10-12,1 Hz,9 harmonic tremor 11-20,9 Hz, swarm 11-12,3 Hz, local tectonic 11,9-12,6 Hz, far tectonic 2,62-12,6 Hz, blowing 4,88-12,8 Hz, low frequency 0,47-3,17 Hz, tornillo 12-12,6 Hz. Volcanic hypocenter erthquakemostly occurred in Lewotobi laki-laki and local tectonic occurred on southwest of mount Lewotobi. The value of b-value obtained was 1,12 ± 0,18. From the result of analysis not founded a direct correlation of volcanic and tectonic activity.