Implementation of Filter Picker Algorithm For Aftershock Identification of Lombok Earthquake 2018

  • A. Ardianto Volcanology and Geothermal Laboratory, Geophysical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung
  • Y.M. Husni Lab Vulkanologi dan Panas Bumi, Teknik Geofisika, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung (ITB), Bandung, Indonesia
  • A. D. Nugraha Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • M. Muzli Badan Meteorologi, Klimatologi, dan Geofisika (BMKG), Jakarta, Indonesia; Earth Observatory of Singapore (EOS), Nanyang Technological University Singapore
  • Z. Zulfakriza Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • H. Afif Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), Bandung, Indonesia
  • David P. Sahara Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • Sri Widiyantoro Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • Awali Priyono Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • Nanang T. Puspito Kelompok Keahlian Geofisika Global, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung
  • Pepen Supendi Badan Meteorologi, Klimatologi, dan Geofisika (BMKG), Jakarta, Indonesia
  • A. Riyanto Badan Meteorologi, Klimatologi, dan Geofisika (BMKG), Jakarta, Indonesia
  • Shengji Wei Earth Observatory of Singapore (EOS), Nanyang Technological University Singapore
  • B. S. Prabowo Lab Vulkanologi dan Panas Bumi, Teknik Geofisika, Fakultas Teknik Pertambangan dan Perminyakan, Institut Teknologi Bandung (ITB), Bandung, Indonesia

Keywords

Aftershock Identification, Lombok 2018 Event, Automatic Arrival Time Pick, Filter Picker

Abstract

The ability to identify earthquake events that are consistent, efficient and accurate is increasingly needed along with the increase in the amount of data analyzed. In this paper a filter picker algorithm is implemented to identify aftershock  events and determination of arrival time automatically, especially for the P wave phase. Here modifications are made in determining the uncertainty of arrival time and there are additional criteria in determining the time of arrival used. The additional criteria are that in a certain time span, there are at least 5 stations determined by the time the filter picker arrives. This is done to minimize identification errors due to local noise and other practical reasons, namely the minimum number of stations to determine the location and other seismological analysis. To test the filter picker algorithm, aftershock data from the Lombok earthquake occurred on July 29 (M 6.4), August 5 (M 7), and August 19 (M 6.3 and M 6.9)  2018. The aftershock data were used for 30 days, from August 4, 2018 to September 4, 2018 using local seismic station in Lombok Island. The results of the filter picker algorithm were evaluated by comparing the number of earthquake events detected and the accuracy of determining the P wave arrival time automatically to the results of manually arriving time. In addition, a comparison of the results obtained from a broadband type seismometer with a short period is used to find out how much influence the type of tool has on its performance results. The results of the comparison with the manual arrival time show that more than 85 percent of the results of the automatic arrival time have a difference below 0.2 seconds. Therefore, it can be said that the filter picker algorithm is quite effective for identifying events and determining the arrival time of P waves. In this paper it is also shown that this algorithm can be used for broad band and short period seismometer sensor, even without the prior correction of instruments.

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Published
Sep 3, 2019
How to Cite
ARDIANTO, A. et al. Implementation of Filter Picker Algorithm For Aftershock Identification of Lombok Earthquake 2018. Jurnal Geofisika, [S.l.], v. 17, n. 1, p. 25-31, sep. 2019. ISSN 2477-6084. Available at: <https://jurnal-geofisika.or.id/index.php/jurnal-geofisika/article/view/397>. Date accessed: 20 sep. 2019.