Shindy Rosalia

• Master's Student at Bandung Institute of Technology

The condition and amount of earthquake data in the world continues to increase along with the increasing capacity and coverage of the global seismic network. Therefore, there is a need for technology that can accommodate the increasing amount of data and process it quickly to help improve data processing efficiency in identifying seismic wave phase...

The Sunda Strait lies between two distinct tectonic regions with perpendicular and oblique subduction in Java and Sumatra, respectively. The region experiences significant seismic activity, with an active volcanic ring resulting from the collision between the Indo-Australian and Eurasian plates. In this research, we employed 3-D velocity tomography...

Because of its well-documented subduction zone and outer island arc, Sumatra provides a unique setting for studying and forecasting earthquakes within the seismically active Sunda Arc. This study builds on previous research that utilized Global Positioning System data and the Akaike information criterion to analyze probabilistic seismic hazard func...

The existence of back-arc thrust faults along the eastern part of the Sunda Arc, ranging westwards from Flores to the western tip of Java, has been recognised for decades. In contrast, it is still unknown whether such back-arc thrust faults exist in Sumatra, which is located in the western part of the Sunda Arc. To investigate the possible existenc...

Kalimantan and Sulawesi are located within the complex tectonic setting of central Indonesia. The tectonic evolution process during the Mesozoic and Cenozoic led to the formation of this region. Studies of Moho depth variation beneath this region are still limited due to the lack of local to regional scale seismic stations covering the entire Kalim...

Borneo and Sulawesi are two large islands separated by the Makassar Strait that lie within the complex tectonic setting of central Indonesia. The seismic structure beneath this region is poorly understood due to the limited data availability. In this study, we present Rayleigh wave tomography results that illuminate the underlying crustal structure...

The western part of Java is situated near various geological formations stemming from the collision between the Indo-Australian and Eurasian tectonic plates. These formations include the Java Trench, Sunda Strait, and several active onshore faults, rendering the area susceptible to seismic activity. The dynamic response of the soil to seismic shaki...

Indonesia’s tectonic setting has resulted in a high level of seismic activity, which makes seismic networks and early warning systems vital for this country. Indonesia’s seismic stations, a total of 411 stations in 2021, are maintained by the Meteorological, Climatological, and Geophysical Agency (BMKG). This study attempts to evaluate station perf...

The Palu Koro Fault, which frequently causes solid and destructive earthquakes, is the most exciting aspect of Central Sulawesi’s tectonics. We used local earthquake data from the area in this preliminary study. Our preliminary investigation entails analyzing local seismic data and estimating the velocity structure and hypocenter location using a t...

Tangkuban Parahu is an active volcano in Indonesia that is part of the Quaternary Sunda volcanic arc. We used the vertical component of waveform recorded by 55 temporary seismic stations deployed around Tangkuban Parahu volcano from October 2021 to February 2022 to gain a thorough understanding of its seismic structure. To extract empirical Green’s...

Spectral analysis method is commonly used in estimating moment magnitude for small to medium size earthquake. Most moment magnitude studies have been focused on the consistency of the average values with other methods. However, little attention is put into the study of moment magnitude sensitivity to its input parameter. In this study we attempted...

This paper presents the depth inversion of Rayleigh wave group velocity to obtain an S-wave velocity model from seismic ambient noise cross-correlation in western Java, Indonesia. This study utilizes the vertical component data of a temporary seismograph network deployed in 2016, which was used in a previous study to estimate fundamental mode Rayle...

The Molucca Sea Plate, and Sangihe and Halmahera plates have a complex tectonic setting and interact to create the Molucca Sea Collision Zone. We re-picked 1647 events recorded from 2010 to 2017 from 32 of The Agency for Meteorology, Climatology, and Geophysics (BMKG) stations and obtained P- and S-arrivals of ~17,628 phases. Hypocenter locations w...

The Lembang Fault is located about eight km north of Bandung City, the capital city of the West Java province of Indonesia, with about 8.79 million people (dated 2020). Several studies state that the Lembang fault is an active fault with a maximum magnitude of 6.5 to 7. In terms of earthquake disaster mitigation, distinguishing characteristics of s...

This study’s research aim has been to clearly reveal the geometry of the Molucca Sea Plate subduction zone beneath Sulawesi’s north arm, the relationship between the subduction zone and volcanic activity in Halmahera, and analyze the depths of the upper arch of the double subduction of the Molucca Sea Plate. The use of travel time tomography made i...

The Banyumas Basin is one of a sedimentary basins in the southern coast of Central Java that has many manifestations of the presence of hydrocarbons in the form of oil and gas seeps found on the surface. Its presence is covered by a thick subvulcanic sedimentary layer. A conventional seismic active method which is usually used to delineate subsurfa...

In 2006, the Special Region of Yogyakarta was shaken by a destructive earthquake. The United States Geological Survey (USGS) recorded that the earthquake had a magnitude of 6.3 M w at a depth of 12.5 km below the surface that was triggered by strike slip fault activity. The severe damage occurred in Bantul district and Klaten district, where the Kl...

Java Island is one of the areas with a population density of 1,171 people/km ² , which is relatively high compared to other regions in Indonesia. The tectonic setting of the Java region is affected by the interaction of tectonic plate subduction between the Indo-Australian Plate and the Eurasian Plate which moves at the rate of 67 mm/year. In addit...

West Java, Indonesia, is located in the northern part of the subduction zone between the Australian and Eurasian plates, with a complex tectonic setting and high seismicity level. In 2016, Institut Teknologi Bandung (ITB) and Australia National University (ANU) deployed 85 temporary seismometers to investigate this area. We constructed the shallow...

Subsurface images of an area with a thick volcanic layer generally cannot be well-imaged with conventional seismic exploration (seismic reflection) due to seismic wave scattering. Another method is needed to obtain an accurate subsurface image in a thick volcanic layer area. In this study, we applied ambient noise tomography (ANT) to image the shea...

The island of Ambon lies on complex tectonics, part of Banda Arc which is driven by the Australia – Eurasia collision. Historical earthquake data show that an earthquake resulting the greatest tsunami in Indonesia had occurred at Ambon Island. On 26 September 2019, Ambon was shaken by an M 6.5 earthquake at a depth of 10 km (BMKG). In this study, w...

The Ambon Mw 6.5 earthquake on September 26th, 2019, had contributed to give severe damages and significantly increased seismicity around Ambon Island and surrounding areas. Mainshock was followed by aftershocks with spatial distribution added to the impact of destructions in this region. We investigated aftershocks sequences to reveal the effect o...

Ambient seismic noise tomography is one of the most widely used methods in seismological studies today, especially after a comprehensive Earth noise model was published and noise analysis was performed on the IRIS Global Seismographic Network. Furthermore, the Power Spectral Density technique was introduced to identify background seismic noise in t...

Molucca Sea collision zone is a region which has very complex geology and tectonic setting, producing high seismicity and volcanoes activities. In this study, we have determined hypocenter location around the region using local & regional network of Agency of Meteorology, Climatology, and Geophysics, Indonesia (BMKG). We used 1,647 events that reco...

On September 26, 2019, an earthquake (Mw 6.5) occurred in the northern part of Ambon Island, Molucca, East Indonesia. The National Authority show this earthquake caused infrastructures damage and 28 fatalities. Up to October 31, 2019, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) seismic network had recorded 479 aftersho...

The Banyumas Basin is a tertiary sedimentary basin located in southern Central Java, Indonesia. Due to the presence of volcanic deposits, 2-D seismic reflection methods cannot provide a good estimation of the sediment thickness and the subsurface geology structure in this area. In this study, the passive seismic tomography (PST) method was applied...

This paper presents the depth inversion of Rayleigh wave group velocity to obtain an S-wave velocity model from seismic ambient noise cross-correlation in the western part of Java, Indonesia. This study utilizes the vertical component data of a temporary seismograph network deployed in 2016, which was used in a previous study to estimate fundamenta...

This study provides an attempt to analyze the pre-eruptive seismicity events for volcano eruption forecasting. After more than 50 years of slumber, Agung volcano on Bali Island erupted explosively, starting on November 21, 2017. The eruption was preceded by almost 2 months of significant increase of recorded seismicity, herein defined as “seismic c...

We develop and present a three-dimensional (3D) seismic velocity model of the source region of the 2018 Lombok, Indonesia earthquakes by employing local earthquake tomography. The data consist of 28,728 P- and 20,713 S-wave arrival times from 3,259 events which were recorded by 20 local seismic stations. The results show that most of the significan...

Local seismic tomography is a well-known and commonly used method for obtaining detailed information about the internal structure of volcanoes. The eruption of Mt. Agung in 2017 was a vital opportunity scientifically because it is the first eruption that had sufficient seismic observation networks to carry out local seismic tomography at this volca...

We have successfully conducted the first ambient noise tomography on the island of Lombok, Indonesia using local waveform data observed at 20 temporary stations. Ambient noise tomography was used to delineate the seismic velocity structure in the upper crust. The waveform data were recorded from August 3rd to September 9th, 2018, using short-period...

Local earthquake data was used to determine a three-dimensional (3D) seismic attenuation structure around the aftershock source region of the 2018 Lombok earthquake in Indonesia. The aftershocks were recorded by 13 seismic stations from August 4 to September 9, 2018. The selected data consist of 6,281 P-wave t∗ values from 914 events, which had goo...

Subsurface images of an area with a thick volcanic layer generally can not be well-imaged with conventional seismic exploration (seismic reflection) due to seismic wave scattering. Another method is needed to obtain an accurate subsurface image in a thick volcanic layer area. In this study, we applied Ambient Noise Tomography (ANT) to image the she...

This article presents earthquake catalogs of the 2019 Ambon aftershocks compiled from regional the Agency for Meteorology, Climatology, and Geophysics of Indonesia (BMKG) and local seismic networks deployed in [1]. The final earthquake catalogs are comprised of 1,009 and 1,764 aftershocks compiled from regional [2] and local network [1], respective...

On September 26, 2019, a significant, Mw 6.5, earthquake shook Ambon region, Indonesia, causing severe damage on the Island(s) of Ambon. Due to the complexity of the fault network and in-situ stress field it was, up to now, not possible to define the fault plane using data from the BMKG regional seismic network. In this study, we analyze the fault...

Because of its robustness and practicality, the Horizontal-to-Vertical Spectral Ratio (HVSR) method has been widely used to obtain subsurface structure, mainly the sediment thickness that resides over bedrock. The method uses Fourier Transform to obtain frequency spectrum and calculate the H/V ratio. However, the conventional Fourier Transform meth...

High seismicity rates in eastern Indonesia occur due to the complex interaction of several tectonic plates which resulted in two deadly, destructive earthquake sequences that occurred in Lombok Island and the city of Palu, Sulawesi in 2018. The first sequence began in July with an Mw 6.4 event near Lombok, culminating in an Mw 7.0 event eight days...

The Agung-Batur Volcanic Complex (ABVC), part of the Sunda volcanic arc, is the source of some of the most hazardous volcanic activity in Indonesia. The ABVC has undergone many small (VEI 1-2) eruptions since historical records began in the early 19th century, but Mt. Agung has experienced much larger (VEI 5) eruptions, both in the modern (1963) an...

S U M M A R Y We investigated the seismic shear wave velocity structure of the upper crust beneath the Ban-dung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After interstation cross-correla...

S U M M A R Y We investigated the seismic shear wave velocity structure of the upper crust beneath the Ban-dung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After interstation cross-correla...

In this paper, we compare two different methods for group velocity inversion: iterative, least-squares subspace optimization, and probabilistic sampling based on the Trans-dimensional Bayesian method with tree-based wavelet parameterization. The wavelet parameterization used a hierarchical prior for wavelet coefficients which could adapt to the dat...

In the past 2 years, we have been conducting routine hypocenter relocation in Indonesia. We compiled and conducted hypocenter relocation of ~50.000 events from a magnitude of 1.4 to 8.5 recorded by 451 stations around and outside Indonesia region. We used local, regional, and teleseismic arrival time data from Indonesian Agency of Meteorology, Clim...

Java Island is highly active tectonic zone and also has a complex geological system as a result of Indo-Australian plate that subducted under the Eurasian plate. This complexity produces many large and destructive earthquakes. Moreover, Java is a most densely populated region in Indonesia. The precise earthquake location can define and evaluate the...

Lembang Fault is located in the Bandung basin with is a thick sedimentary of volcanic rocks and the depositional remnants of an ancient lake. Bandung region has a dense population and infrastructure that possible to be vulnerable of seismic hazard. Based on geological studies, Lembang fault is an active fault that possibility to produce a magnitude...

On May 14th and 18th, 2017 felt earthquakes were occurred around western part of Lembang area, Bandung, West Java, Indonesia with magnitude of M2.8 and M2.9, respectively. The first earthquake (M2.8) was felt by some people around epicenter area. We determined the earthquake location through re-picking of P-and S-wave arrival time recording by Indo...

West Java in the western part of the Sunda Arc has a relatively high seismicity due to subduction activity and faults. In this study, double-difference tomography was used to obtain the 3D velocity tomograms of P and S waves beneath the western part of Java. To infer the geometry of the structure beneath the study area, precise earthquake hypocente...

The Special Region of Yogyakarta has experienced a fairly high seismic activity due to its location in an active tectonic setting. One of the active fault in this region is the Opak fault which has striking south west - north east. In this study, we analyzed aftershocks sequence through waveform data which taken from 16 temporary GeoForschungsZentr...

This study investigates the coseismic slip distribution of the 2 July 2013 Mw 6.1 Aceh earthquake using Global Positioning System (GPS) data, measured geological surface offsets, and an aftershock distribution for a period of four days after the mainshock. We use the aftershock distribution to constrain the fault-plane strike of a right-lateral fau...

The earthquake swarm events sequence occurred in west Halmahera, north Molucca, Indonesia for the period of October 2015 to February 2016 as reported by Meteorological, Climatological, and Geophysical Agency (BMKG) of Indonesia. There were tenths swarm events with Magnitude larger than four in the region during the period. In this study, we used th...

West Java, part of the Sunda Arc, has relatively high seismicity due to subduction activity and faulting. The first step of tomography study in order to infer the geometry of the structure beneath West Java is to conduct precise earthquake hypocenter determination. In this study, we used earthquake waveform data taken from the regional Meteorologic...