Seismic Attenuation Tomography From 2018 Lombok Earthquakes, Indonesia

Priyono, Awali; Nugraha, Andri Dian; Muzli, Muzli; Ardianto, Ardianto; Aulia, Atin Nur; Prabowo, Billy Sugiartono; Zulfakriza, Zulfakriza; Rosalia, Shindy; Sasmi, Annisa Trisnia; Afif, Haunan; Sahara, David P.; Widiyantoro, Sri; Wei, Sui; Husni, Yayan Mi’rojul; Sarjan, Achmad Fajar Narotama

doi:10.3389/feart.2021.639692

Cited by 5 publications

(10 citation statements)

References 56 publications

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“…Sasmi et al (2020) explained that the 2018 Lombok earthquake aftershocks were mostly distributed to the depth of < 20 km with an average hypocenter slope of ~30 o and thought to be related with the rupture zone of 2018 Lombok earthquake. These significant events of earthquake were suspected as a result of the oceanic crust slabbed to the north of Lombok Islands and caused fault segmentation (Sasmi et al, 2020;Afif et al, 2021;Priyono et al, 2021;Wang et al, 2020;Salman et al, 2020;Yang et al, 2020;Lythgoe et al, 2021). The results from these studies confirm that the lack of correlation between event depths and δt suggests the shallow anisotropic fabrics may control the main possible sources of anisotropy in this area.…”

Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 59%

“…This may be related to the influence of the crack zone formed during the 2018 Lombok significant earthquake (Sasmi et al, 2020;Afif et al, 2021;Priyono et al, 2021;Wang et al, 2020;Salman et al, 2020). Sasmi et al (2020) explained that the 2018 Lombok earthquake aftershocks were mostly distributed to the depth of < 20 km with an average hypocenter slope of ~30 o and thought to be related with the rupture zone of 2018 Lombok earthquake.…”

Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 99%

“…Rinjani volcanic system (Afif et al, 2021;Sundhoro et al, 2000), or fluid related to the subduction system of oceanic crust in the north of Lombok (Afif et al, 2021;Priyono et al, 2021;Yang et al, 2020) contributes to the crustal anisotropy beneath the Lombok Island. The presence of fluid in the microcrack systems can preclude the microcracks to close producing higher degree of anisotropy.…”

Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 99%

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Shear Wave Splitting of the 2018 Lombok Earthquake Aftershock Area, Indonesia

Sasmi

Nugraha

Muzli

et al. 2022

Preprint

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Lombok is one of the islands in the transitional zone from the Sunda Arc to the Banda Arc, Indonesia. In the mid-2018, the island of Lombok was shaken by a series of strong earthquakes, started with a magnitude 6.4 earthquake on July 29, 2018 followed by earthquakes on August 5 (M 7.0), August 9 (M 5.9), and August 19 (M 6.3 and 6.9). Some researchers suggested that this phenomenon occurred due to a segmentation rupture in the northern part of Lombok Island. This study aims to obtain information on the distribution of the Lombok earthquake rupture zone 2018, through Shear Wave Splitting (SWS) study. Splitting, or S-wave separation, occurs when the S-wave passes through an anisotropic medium. The S wave is split into fast and slow S waves with almost orthogonal polarizations and has parameters such as delay time and polarization direction of the fast S wave. To determine the SWS parameters, we used a Lombok earthquake aftershock data set recorded from 4 August to 9 September 2018, using 16 seismographic stations. The steps taken to obtain the SWS parameters are event selection, windowing using short time Fourier transform, and rotation-correlation process. The results of the SWS analysis indicate that the fast polarization directions probably have a linkage with the local fault system and the fault related to the Lombok earthquake rupture zone.

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Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 59%

Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 99%

Section: The Influence Of Structure Induced Anisotropymentioning

confidence: 99%

See 1 more Smart Citation

Shear Wave Splitting of the 2018 Lombok Earthquake Aftershock Area, Indonesia

Sasmi

Nugraha

Muzli

et al. 2022

Preprint

Self Cite

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“…However, the difference is in the structure's location, which is in Lombok's northern region (Widyarta et al, 2020). Another tomographic study by Afif et al (2021) and Priyono et al (2021) found that aftershocks formed an east-west cluster due to the low seismic velocities of the local medium. High temperature, fluid, and numerous fractures are indicated by this.…”

Section: Resultsmentioning

confidence: 99%

Existence of Faults that Cause Earthquakes on Lombok Island: A Critical Literature Review

Bunaga¹,

Rosid

Anggono

2022

jppipa, pendidikan ipa, fisika, biologi, kimia

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This study qualitatively elaborates fault characteristics causing earthquakes in Lombok Island. Historically, Lombok Island has been 12 destructive and significant earthquakes in period of 1979 – 2018. Therefore, the island is in an earthquake-prone region. The hazard factor is one of the key factors in assessing risk. This study become important as their potential to have a big impact. A source of activity that has not been fully investigated in detail was the location of the recent major and devastating earthquake (East Lombok earthquake 2019). Consequently, there is a chance that the level of risk on the Island of Lombok will rise. According to the study’s results, a thorough investigation is required to identify and pinpoint the cause of the 2019 Lombok earthquake in order to improve the earthquake risk index and help the local government to reduce losses due to earthquakes.

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“…Persamaan dari perhitungan kecepatan rupture gempa menggunakan Persamaan (2). (Priyono et al, 2021;Supendi et al, 2020). Hal ini didukung pula bahwa sejak 2005 pulau Lombok meningkat aktivitas seismik atau seismisitasnya khususnya di daerah back arc thrust di bagian Utara wilayah Lombok dibandingkan zona subduksi Lempeng Indo-Australia dengan Lempeng Eurasia bagian Selatan (Zubaidah et al, 2014).…”

Section: Teknik Pengolahan Dataunclassified

Pencitraan Rupture Gempabumi Di Lombok Timur Mw 6,9 Pada 19 Agustus 2018 Dengan Metode Back Projection

Ambarsari

Madlazim

Deta

2021

IFI

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Abstrak Gempabumi yang terjadi di Lombok pada 19 Agustus 2018 berkekuatan Mw 6,9 merupakan gempa mainshock kedua sebagai akibat dari rangkaian gempabumi Lombok pada Juli – Agustus 2018. Penelitian ini bertujuan untuk meneliti karakteristik rupture gempabumi di Lombok Timur Mw 6,9 yang terjadi pada tanggal 19 Agustus 2018 dari hasil pencitraan arah, kecepatan, durasi, dan panjang rupture gempabumi. Metode yang digunakan dalam penelitian ini dengan teknik pemrosesan array teleseismik menggunakan metode Multiple Signal Back-Projection (MUSICBP) dalam software MATLAB. Data yang digunakan adalah data sekunder dari data seismogram teleseismik dengan 54 stasiun-stasiun seismik array AU (Australia) berformat .SAC dari repositori IRIS Wilber 3. Data tersebut diolah dengan menggunakan program MUSICBP serta dilakukan filter bandpass dengan rentang frekuensi 0,05 – 0,25 Hz melalui proses cross correlation. Hasil keluaran yang diperoleh berupa plot durasi, arah, dan panjang rupture gempa dari MUSICBP serta nilai kemiringan grafik untuk menentukan kecepatan dari rupture gempa dari hasil regresi linear. Hasil dari penelitian ini menunjukkan bahwa pencitraan rupture menggunakan metode MUSICBP adalah sesuai yang divalidasi dengan lokasi gempa susulan-gempa susulan (aftershock) yang terjadi di zona segmentasi rupture tersebut. Berdasarkan hasil dan pembahasan, pada penelitian ini dapat disimpulkan bahwa karakteristik rupture yang terjadi pada gempabumi di Lombok Timur Mw 6,9 tanggal 19 Agustus 2018 adalah arah rupture merambat ke arah Timur secara unilateral sepanjang ~25 km berdurasi 25 s dengan kecepatan rupture 1,74 km/s yang termasuk dalam rentang kecepatan rendah. Hasil dari pencitraan rupture menunjukkan gempabumi yang terjadi di Lombok Timur pada 19 Agustus 2018 tersebut disebabkan oleh aktivitas Flores back arc thrust di wilayah Pulau Lombok bagian Utara dengan arah rupture merambat menuju ke arah Timur (eastward) dengan mekanisme tipe sesar naik (thrust fault). Kata Kunci: Rupture Gempa, Back Projection, Gempa Teleseismik, Sesar Flores Back-Arc. Abstract The earthquake that occurred in Lombok on August 19, 2018, with a magnitude of Mw 6.9 was the second mainshock earthquake as a result of the Lombok earthquake series in July – August 2018. This study aims to examine the characteristics of the earthquake rupture in East Lombok Mw 6.9 which occurred on 19 August 2018 from the results of imaging the direction, speed, duration, and length of earthquake rupture. The method used in this research is a teleseismic array processing technique using the Multiple Signal Back-Projection (MUSICBP) method in MATLAB software. The data used is secondary data from teleseismic seismogram data with 54 AU (Australia) seismic array stations in .SAC format from the IRIS Wilber 3 repository. The data was processed using the MUSICBP program and a bandpass filter was performed with a frequency range of 0.05 – 0.25 Hz through the cross-correlation process. The outputs obtained are plots of duration, direction, and length of earthquake rupture from MUSICBP and the slope value of the graph to determine the velocity of earthquake rupture from linear regression results. This study indicates that the rupture imaging using the MUSICBP method is appropriate which is validated by the location of the aftershocks that occur in the rupture segmentation zone. Based on the results and discussion, in this study, it can be concluded that the characteristics of the rupture that occurred in the earthquake in East Lombok Mw 6.9 on 19 August 2018 were the direction of the rupture spreading towards the East unilaterally along ~25 km with a duration of 25 s with a rupture speed of 1.74 km/s which is included in the low-speed range. The results of the rupture imaging show that the earthquake that occurred in East Lombok on August 19, 2018, was caused by the activity of Flores back arc thrust in the northern part of Lombok Island with the direction of the rupture spreading towards the East (eastward) with a thrust fault type mechanism. Keywords: Earthquake Rupture, Back Projection, Teleseismic Earthquake, Flores Back-Arc Thrust.

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Seismic Attenuation Tomography From 2018 Lombok Earthquakes, Indonesia

Cited by 5 publications

References 56 publications

Shear Wave Splitting of the 2018 Lombok Earthquake Aftershock Area, Indonesia

Shear Wave Splitting of the 2018 Lombok Earthquake Aftershock Area, Indonesia

Existence of Faults that Cause Earthquakes on Lombok Island: A Critical Literature Review

Pencitraan Rupture Gempabumi Di Lombok Timur Mw 6,9 Pada 19 Agustus 2018 Dengan Metode Back Projection

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