Earthquake Monitoring Using Variometric GPS Data Processing

Variometric Approach for Standalone Engine Displacement Analysis (VADASE) is a technique used in seismology purposes using GPS measurements. VADASE is used to determine the small displacement from the earthquake. The VADASE L1 solution is using the klobuchar ionospheric model. In this study VADASE was used in earthquakes with magnitudes> 7 to> 9 righter scales. In the scale of the earthquake category> 9 used Indian Ocean earthquake of December 26, 2016 with the strength of 9.1 SR by using the closest SAMP station and the Japanese Tohoku earthquake of March 11, 2011 with a power of 9.1 SR using 4 different stations namely MIZU, KMSV, TSK2 and Knii . The earthquake category with a scale of> 8 SR is the offshore earthquake Bio Bio, Chile on February 27, 2010 with a power of 8.8 SR using 2 stations namely ANTC and SANT, the Bengkulu Indonesia earthquake on 12 September 2007 with a power of 8.4 SR using the SAMP station, an illaper earthquake, chile September 16 2015 with 8.3 SR using SANT station, and Tres Piscos earthquake Mexico on September 8, 2017 with a power of 8.2 SR using IENG station. Earthquake with a strength of> 7 SR, namely the amberlay-New Zealand earthquake on November 13, 2016 with a strength of 7.8 SR using MRLL and WGTN stations, Puerto quello-chile earthquake on December 25, 2016 with a strength of 7.6 SR using COYQ station, Java sea earthquake -Indonesia on 8 August 2007 with 7.5 SR power using BAKO station and ayula mexico earthquake on 19 september 2017 with 7.1 SR power using INEG station. From the results of VADASE, the farthest distance from the epicenter to the observation station is 1100 km (INEG station) and the closest distance is 95 km (BAKO station). The highest speed is 0.12 m / s after 5 minutes from the earthquake in the earthquake Offshore Bio Bio-Chile 2010 uses the SANT station and the lowest speed is 0.006 m / s after 10 minutes from the earthquake in the 2007 Bengkulu earthquake using the SAMP station. Whereas in the other earthquakes was the 2011 Tohoku earthquake with a speed of 0.06 m / s after 1 minute using MIZU station, the amberley-New Zealand earthquake 2016 with a speed of 0.015 m / s after 1 minute using the MRLI satellite, Puerto quelloearthquake Chile 2016 with a speed of 0.025 m / s after 40 minutes using the COYQ satellite

Tomografi 3D dari Anomali Ionosfer Tepat Setelah Gempa Bumi Menggunakan Data GNSS-TEC (Studi Kasus : Gempa Sumatra Barat 2 Maret 2016 Dan Gempa Palu 28 September 2018)

Global Navigation Satellite System (GNSS) merupakan sistem navigasi yang menggunakan sinyal satelit dalam penentuan posisinya, dimana sistem ini terdiri dari beberapa satelit yang tersusun dalam sistem konstelasi. GNSS mentransmisikan sinyal ke penerima (receiver) di Bumi. Receiver GNSS menentukan posisi pengguna, kecepatan, dan waktu dengan mengolah sinyal yang ditransmisikan oleh satelit. Tujuan awal dari peluncuran GNSS untuk keperluan navigasi, tetapi seiring dengan perkembangannya GNSS dapat dimanfaatkan untuk kepentingan observasi deformasi kerak bumi hingga studi mengenai lapisan atmosfer. Data gelombang yang tertunda ketika melalui ionosfer dapat dimanfaatkan untuk mendapatkan nilai Total Electron Content (TEC) yang selanjutnya digunakan untuk mempelajari gangguan Ionosfer. Gangguan ionosfer disebabkan oleh berbagai fenomena, yang paling sering ditemukan adalah gangguan ionosfer yang disebabkan oleh induksi gelombang akustik dan gravitasi yang dieksitasi oleh gerakan kerak coseismic dari gempa bumi besar. Fenomena ini disebut sebagai Coseismic Ionospheric Disturbances (CID). Dalam penelitian ini, GNSS dimanfaatkan untuk mendapatkan informasi terkait gangguan ionosfer yang terjadi setelah gempa bumi Sumatra Barat tanggal 2 Maret 2016 dan gempa Palu 28 September 2018. Berdasarkan hasil pengolahan data GNSS-TEC didapatkan bahwa CID terdeteksi pada ~15 menit setelah gempa Sumatra Barat 2016 dengan nilai amplitudo maksimum sebesar 1,62 TECU. Sedangkan pada gempa Palu, CID terdeteksi pada ~13 menit setelah gempa dengan amplitudo maksimum sebesar 0,42 TECU. Kecepatan propagasi gelombang CID pada gempa Sumatra Barat 2016 dan Palu 2018, masing-masing adalah 1-1,3 km s-1 dan 0,8-1,6 km s-1. Perambatan gelombang tersebut konsisten dengan kecepatan gelombang akustik. Untuk mendukung analisa spasial yang dilakukan, model 3D tomografi dibuat dan mendapatkan gambaran pada lapisan ionosfer dari ketinggian 100-600 km diatas permukaan laut. Permodelan 3D ionosfer dibuat dengan mempertimbangkan variasi densitas elektron di setiap lapisan ionosfer, dimana pada ketinggian sekitar 300 km di atas permukaan bumi merupakan lapisan yang yang dominan mengandung anomali yang tinggi. Uji akurasi checkerboard (papan catur) juga dilakukan untuk melakukan uji kehandalan dari model 3D tomografi. ================================================================================================ Global Navigation Satellite System (GNSS) is a navigation system that uses satellite signals in determining its position, where this system consists of several satellites arranged in a constellation system. GNSS transmits signals to receivers on Earth. The GNSS receiver determines the user's position, speed, and time by processing the signals transmitted by the satellites. The initial purpose of launching the GNSS was for navigation purposes, but along with its development, GNSS can be used for the purposes of observing deformation of the earth's crust to studying the atmosphere. Delayed wave data when passing through the ionosphere can be used to obtain the Total Electron Content (TEC) value which is then used to study ionospheric disturbances. Ionospheric disturbances are caused by various phenomena, the most common of which is ionospheric disturbances caused by the induction of acoustic and gravitational waves excited by coseismic crustal motions from large earthquakes. This phenomenon is known as Coseismic Ionospheric Disturbances (CID). In this study, GNSS was used to obtain information related to ionospheric disturbances that occurred after the West Sumatra earthquake on March 2, 2016 and the Palu Earthquake on September 28, 2018. Based on the results of GNSS-TEC data processing, it was found that CID was detected at ~15 minutes after the 2016 West Sumatra Earthquake. with a maximum amplitude value of 1.62 TECU. Whereas in the Palu Earthquake, CID was detected at ~13 minutes after the earthquake with a maximum amplitude of 0.42 TECU. The propagation speed of CID waves in the 2016 West Sumatra and Palu 2018 earthquakes were 1-1.3 km s-1 and 0.8-1.6 km s-1, respectively. The wave propagation is consistent with the speed of the acoustic wave. To support the spatial analysis carried out, a 3D tomographic model was created and obtained an overview of the ionosphere layer from an altitude of 100-600 km above sea level. The ionosphere 3D modeling is made by considering the variation of electron density in each layer of the ionosphere, where at an altitude of about 300 km above the earth's surface is the dominant layer containing high anomalies. The checkerboard accuracy test was also carried out to test the reliability of the 3D tomography model

Pengaruh Koreksi Bias Ionosfer Terhadap Hasil Koordinat Pengamatan GPS Single Frequency Menggunakan Model Klobuchar

Sinyal satelit GPS dipengaruhi oleh beberapa faktor kesalahan, di antaranya penundaan sinyal GPS oleh ionosfer. Pada GPS single frequency bias ini dapat dikoreksi menggunakan Model Klobuchar, yang memperkirakan penundaan waktu ionosfer hingga 50% atau lebih. Untuk menggunakan model Klobuchar membutuhkan delapan koefisien Klobuchar (αn, βn, untuk n = 1,2,3,4) dan disediakan melalui pesan navigasi. Koefisien Klobuchar didapatkan dari perhitungan data pengamatan GPS yang terdistribusi di seluruh dunia dengan metode yang tidak terpublikasi. Dalam Tugas ini, satu set koefisien Klobuchar dihitung menggunakan data pengamatan GPS lokal sehari sebelumnya dan digunakan sebagai parameter navigasi pada hari selanjutnya untuk menentukan koordinat titik pengamat. Tugas akhir ini melakukan perhitungan nilai Delay ionosphere dan Total Electron Content selama waktu pengamatan menggunakan algoritma Klobuchar. Hasil tugas akhir ini didapatkan nilai koordinat meningkat sebesar 26,015% dengan menggunakan koefisien lokal. ============================================================GPS satellite signals are influenced by several kinds of error factors, among which the GPS signal delay by the ionosphere. For GPS single frequency receiver this delay can be estimated using Klobuchar Model, which estimate ionospheric time delay up to 50% or more. In order to use the Klobuchar model requires eight Klobuchar coefficients (αn, βn, for n=1,2,3,4) and they are provided through the navigation messages. Klobuchar coefficients are calculated by combining the worldwide distributed GPS station’s observation data with unpublished method. In this thesis, a set of new Klobuchar Ionospheric model coefficient computed on ground using previous data and broadcasted as secondary navigation parameters to the user to determine the user’s coordinates. This thesis estimated the Ionospheric delay, and Total Electron Content of ionosphere during the time of observation using the Klobuchar algorithm. As a result,is obtained by increasing the coordinate value of 26.015% by using local coefficients

Harmonic ionospheric oscillation by the 2010 eruption of the Merapi volcano, Indonesia, and the relevance of its amplitude to the mass eruption rate

Using continuous data from ground-based Global Satellite Navigation System (GNSS) receivers in Java and Sumatra, Indonesia, we studied the response of ionospheric total ionospheric electron content (TEC) to the 2010 Nov.5 eruption of the Merapi volcano in central Java. We then compared the results with the case of the 2014 Feb.13 eruption of the Kelud volcano, eastern Java. The TEC showed a quasi-periodic oscillation of a frequency ~4 mHz with average amplitudes of 0.9 and 1.8% relative to background values lasting for ~20 and ~ 120 min for the Merapi and Kelud eruptions, respectively. By comparing the two cases, together with the 2015 April eruption of the Calbuco volcano, Chile, we found the relative TEC oscillation amplitude may scale with the mass eruption rate. This suggests that the product of such TEC oscillation amplitude and the duration provides a new measure for the total volume of the volcanic deposits

Earthquake Monitoring Using Variometric GPS Data Processing

Variometric Approach for Standalone Engine Displacement Analysis (VADASE) is a technique used in seismology purposes using GPS measurements. VADASE is used to determine the small displacement from the earthquake. The VADASE L1 solution is using the klobuchar ionospheric model. In this study VADASE was used in earthquakes with magnitudes> 7 to> 9 righter scales. In the scale of the earthquake category> 9 used Indian Ocean earthquake of December 26, 2016 with the strength of 9.1 SR by using the closest SAMP station and the Japanese Tohoku earthquake of March 11, 2011 with a power of 9.1 SR using 4 different stations namely MIZU, KMSV, TSK2 and Knii . The earthquake category with a scale of> 8 SR is the offshore earthquake Bio Bio, Chile on February 27, 2010 with a power of 8.8 SR using 2 stations namely ANTC and SANT, the Bengkulu Indonesia earthquake on 12 September 2007 with a power of 8.4 SR using the SAMP station, an illaper earthquake, chile September 16 2015 with 8.3 SR using SANT station, and Tres Piscos earthquake Mexico on September 8, 2017 with a power of 8.2 SR using IENG station. Earthquake with a strength of> 7 SR, namely the amberlay-New Zealand earthquake on November 13, 2016 with a strength of 7.8 SR using MRLL and WGTN stations, Puerto quello-chile earthquake on December 25, 2016 with a strength of 7.6 SR using COYQ station, Java sea earthquake -Indonesia on 8 August 2007 with 7.5 SR power using BAKO station and ayula mexico earthquake on 19 september 2017 with 7.1 SR power using INEG station. From the results of VADASE, the farthest distance from the epicenter to the observation station is 1100 km (INEG station) and the closest distance is 95 km (BAKO station). The highest speed is 0.12 m / s after 5 minutes from the earthquake in the earthquake Offshore Bio Bio-Chile 2010 uses the SANT station and the lowest speed is 0.006 m / s after 10 minutes from the earthquake in the 2007 Bengkulu earthquake using the SAMP station. Whereas in the other earthquakes was the 2011 Tohoku earthquake with a speed of 0.06 m / s after 1 minute using MIZU station, the amberley-New Zealand earthquake 2016 with a speed of 0.015 m / s after 1 minute using the MRLI satellite, Puerto quelloearthquake Chile 2016 with a speed of 0.025 m / s after 40 minutes using the COYQ satellite

Comparison of volcanic explosions in Japan using impulsive ionospheric disturbances

Using the ionospheric total electron content (TEC) data from ground-based Global Navigation Satellite System (GNSS) receivers in Japan, we compared ionospheric responses to five explosive volcanic eruptions 2004-2015 of the Asama, Shin-Moe, Sakurajima, and Kuchinoerabu-jima volcanoes. The TEC records show N-shaped disturbances with a period similar to 80 s propagating outward with the acoustic wave speed in the F region of the ionosphere. The amplitudes of these TEC disturbances are a few percent of the background absolute vertical TEC. We propose to use such relative amplitudes as a new index for the intensity of volcanic explosions

Co-Seismic Ionospheric Disturbances Following the 2016 West Sumatra and 2018 Palu Earthquakes from GPS and GLONASS Measurements

The study of ionospheric disturbances associated with the two large strike-slip earthquakes in Indonesia was investigated, which are West Sumatra on 2 March 2016 (Mw = 7.8), and Palu on 28 September 2018 (Mw = 7.5). The anomalies were observed by measuring co-seismic ionospheric disturbances (CIDs) using the Global Navigation Satellite System (GNSS). The results show positive and negative CIDs polarization changes for the 2016 West Sumatra earthquake, depending on the position of the satellite line-of-sight, while the 2018 Palu earthquake shows negative changes only due to differences in co-seismic vertical crustal displacement. The 2016 West Sumatra earthquake caused uplift and subsidence, while the 2018 Palu earthquake was dominated by subsidence. TEC anomalies occurred about 10 to 15 min after the two earthquakes with amplitude of 2.9 TECU and 0.4 TECU, respectively. The TEC anomaly amplitude was also affected by the magnitude of the earthquake moment. The disturbance signal propagated with a velocity of ~1–1.72 km s−1 for the 2016 West Sumatra earthquake and ~0.97–1.08 km s−1 for the 2018 Palu mainshock earthquake, which are consistent with acoustic waves. The wave also caused an oscillation signal of ∼4 mHz, and their azimuthal asymmetry of propagation confirmed the phenomena in the Southern Hemisphere. The CID signal could be identified at a distance of around 400–1500 km from the epicenter in the southwestern direction