Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012
Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007-2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake’s precu...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
ITB Journal Publisher
2015-03-01
|
| Series: | Journal of Mathematical and Fundamental Sciences |
| Subjects: | |
| Online Access: | http://journals.itb.ac.id/index.php/jmfs/article/view/418 |
| _version_ | 1819208564856586240 |
|---|---|
| author | Suaidi Ahadi Nanang Tyasbudi Puspito Gunawan Ibrahim Sarmoko Saroso Kiyohumi Yumoto Muzli |
| author_facet | Suaidi Ahadi Nanang Tyasbudi Puspito Gunawan Ibrahim Sarmoko Saroso Kiyohumi Yumoto Muzli |
| author_sort | Suaidi Ahadi |
| collection | DOAJ |
| description | Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007-2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake’s precursors, were determined by the Welch ratio SZ/SH at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the SZ/SH power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time. |
| first_indexed | 2024-12-23T05:41:24Z |
| format | Article |
| id | doaj.art-51c8dc54ac394b4b89d789fcb8bb36b5 |
| institution | Directory Open Access Journal |
| issn | 2337-5760 2338-5510 |
| language | English |
| last_indexed | 2024-12-23T05:41:24Z |
| publishDate | 2015-03-01 |
| publisher | ITB Journal Publisher |
| record_format | Article |
| series | Journal of Mathematical and Fundamental Sciences |
| spelling | doaj.art-51c8dc54ac394b4b89d789fcb8bb36b52022-12-21T17:58:11ZengITB Journal PublisherJournal of Mathematical and Fundamental Sciences2337-57602338-55102015-03-014718410310.5614/j.math.fund.sci.2015.47.1.7Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012Suaidi Ahadi0Nanang Tyasbudi Puspito1Gunawan Ibrahim2Sarmoko Saroso3Kiyohumi Yumoto4Muzli5Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Jalan Ganesa No. 10, Bandung 40132, IndonesiaFaculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Jalan Ganesa No. 10, Bandung 40132 IndonesiaFaculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Jalan Ganesa No. 10, Bandung 40132 IndonesiaNational Institute of Aeronautics and Space (LAPAN), Jalan Djujunan No. 133, Bandung 40173 IndonesiaInternational Center Space Weather Science and Education, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, JepangMeteorology Climatology and Geophysical Agency (BMKG), Jalan Angkasa 1 No. 2, Jakarta 10720 IndonesiaEleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007-2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake’s precursors, were determined by the Welch ratio SZ/SH at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the SZ/SH power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time.http://journals.itb.ac.id/index.php/jmfs/article/view/418Dst Indexearthquake precursorpolarization power ratioquiet daySumatrastrong earthquakeULF emission |
| spellingShingle | Suaidi Ahadi Nanang Tyasbudi Puspito Gunawan Ibrahim Sarmoko Saroso Kiyohumi Yumoto Muzli Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 Journal of Mathematical and Fundamental Sciences Dst Index earthquake precursor polarization power ratio quiet day Sumatra strong earthquake ULF emission |
| title | Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 |
| title_full | Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 |
| title_fullStr | Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 |
| title_full_unstemmed | Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 |
| title_short | Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 |
| title_sort | anomalous ulf emissions and their possible association with the strong earthquakes in sumatra indonesia during 2007 2012 |
| topic | Dst Index earthquake precursor polarization power ratio quiet day Sumatra strong earthquake ULF emission |
| url | http://journals.itb.ac.id/index.php/jmfs/article/view/418 |
| work_keys_str_mv | AT suaidiahadi anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 AT nanangtyasbudipuspito anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 AT gunawanibrahim anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 AT sarmokosaroso anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 AT kiyohumiyumoto anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 AT muzli anomalousulfemissionsandtheirpossibleassociationwiththestrongearthquakesinsumatraindonesiaduring20072012 |