Imaging the Geometry of Cimandiri Fault Zone Based on 2D Audio-Magnetotelluric (AMT) Model in Nyalindung, Sukabumi–Indonesia

Arisbaya, Ilham; Handayani, Lina; Mukti, M. Ma’ruf; Sudrajat, Yayat; Grandis, Hendra; Sumintadireja, Prihadi

doi:10.1007/s00024-019-02241-0

Cited by 11 publications

(4 citation statements)

References 29 publications

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“…Along the island, convergence rates decrease from ∼65 mm/yr in East Java to ∼58 mm/yr in West Java (Koulali et al., 2017). Besides the subduction megathrust that accommodates most of the convergence, several active faults affect Java island inland (Figure 1), such as the transpressive Cimandiri (Arisbaya et al., 2019; Marliyani et al., 2016), Lembang (Daryono et al., 2019), and Opak (Walter et al., 2008) Faults. However, E‐W trending compressional faults are less documented in spite of the seismogenic risk.…”

Section: Introductionmentioning

confidence: 99%

Active Back‐Arc Thrust in North West Java, Indonesia

Aribowo

Husson

Natawidjaja³

et al. 2022

Tectonics

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The Java Back‐arc Thrust scars the entire back‐arc area of Java Island, but the faults' nature, timing, and activity remain partly elusive. Characterizing the structure and activity of the seismogenic Java Back‐arc Thrust (historical earthquakes up to 7 Mw) is a cornerstone to evaluate associated geohazards. We focus on the western part of Java Back‐arc Thrust that reaches the megalopolis of Jakarta. We combine morphotectonic data, seismic reflection, electric resistivity profiles, kinematic, structural field measurements, paleoseismological trenching, and sediment dating (optically stimulated luminescence and 14C). Our results suggest that the interplay between the faults, volcanoes, and sedimentary basin modulates the propagation of the fault system across and along‐strike. The West Java Back‐arc Thrust has been active from Pliocene to Recent, but with a laterally variable tempo and tectonic regime. While tectonic activity was sustained for longer times in the eastern part, the West Java Back‐arc Thrust broke through the Jakarta Basin in the west, possibly only since the Late Pleistocene, and partitions into a network of immature transpressive structures. We conclude that the West Java Back‐arc Thrust has a high seismic hazard that requires a careful risk evaluation along its trace, as it threatens the numerous infrastructures of the densely populated West Java.

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Section: Introductionmentioning

confidence: 99%

Active Back‐Arc Thrust in North West Java, Indonesia

Aribowo

Husson

Natawidjaja³

et al. 2022

Tectonics

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“…Current subduction in the south of Java Island is almost trench-perpendicular with a convergence rate from 58 to 65 mm/year from west to east [23]. The neotectonic process generates earthquakes in the subduction megathrust and onshore faults, and most of them rupture in the relatively W-E direction, such as the the Cimandiri [8,24], Lembang [25,26], and Baribis Faults [27,28] in the western part of Java island. Several other seismic activity clusters have been reported with a relative NE-SW direction in the southern part of Java Island in recent years, one of which is the Garsela Fault [29].…”

Section: Geological Settingmentioning

confidence: 99%

Magnetotellurics (MT) and Gravity Study of a Possible Active Fault in Southern Garut, West Java, Indonesia

Arisbaya

Wijanarko

Warsa

et al. 2023

International Journal of Geophysics

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In recent years, dozen low-intensity earthquakes occurred in southern Garut, West Java Indonesia; two of them were reported destructive. However, those shallow earthquake clusters are hardly associated with well-known active faults in the area. Hence, we conducted 3D gravity combined with 2D magnetotellurics (MT) inversions to study the subsurface. Gravity and MT modeling confirm a basin with around 5 km depth consisting of two subbasins separated by a NE-SW trending local-high ridge. The local high coincides with the magmatic intrusion in geothermal fields and aligns with a series of volcanic bodies’ lineament observed on the surface. We interpret this structural high as a preexisting fault that serves as a magma pathway in the tectonomagmatic interaction. Shallow low-magnitude seismicity in the southern Garut area tends to occur in the resistive bodies. We interpret that heat from the cooling magmatic intrusion may decrease the effective fault-normal stress of the rocks, leading to a decrease in fault failure resistance and may initiate rupture. The resistivity structure around the initial rupture may affect whether or not the nucleation will end up as a large-magnitude earthquake. Furthermore, the unconsolidated young volcanic cover in this area could amplify ground shaking when earthquake occurs that might lead to more extensive damage.

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“…In addition, a horizontal to vertical smoothness ratio of 2 was used to enhance the horizontal layering of the resistivity models [15]. The latter is common in the modeling of basins with sedimentary formations, which usually tend to have a layered character [4,18]. The models show that there are conductive areas, indicated as C1, C2 and C3, that reach the deeper part of the subsurface and are consistent with four almost parallel profiles, especially for line-1, line-2 and line-3.…”

Section: Mt Data Modelingmentioning

confidence: 99%

Integrated Magnetotelluric (MT), Gravity and Seismic Study of Lower Kutai Basin Configuration

Irawati¹,

Wang²,

Wijanarko³

et al. 2022

J. Eng. Technol. Sci.

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This work describes a subsurface basin configuration of the Lower Kutai Basin (hereinafter LKB) in East Kalimantan, Indonesia, as inferred from combination of magnetotelluric (MT), seismic, and gravity data. LKB is structurally controlled mainly by the Samarinda Anticlinorium extending in a NNE-SSW direction and is one of the most prolific hydrocarbon basins in Indonesia. The phase tensor analysis of MT data from most stations and frequencies exhibited a 2D character with a relatively low skew (-3° < β < 3°). The geo-electrical strike direction was estimated at N30°E, which is in good agreement with the regional geological strike with a NNE-SSW direction. 2D MT inversion modeling was performed to infer the subsurface resistivity distribution associated with LKB’s configuration. From the integration of MT, seismic and gravity models it was shown that LKB’s configuration is composed mainly of sandstone, black shale, claystone, and basement rocks. The conductive zones of the MT models are associated with thermal alteration of black shale, which changes its mineralization, leading to lower resistivity. Hence, the black shale may be interpreted as potential hydrocarbon source rock in LKB.

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Imaging the Geometry of Cimandiri Fault Zone Based on 2D Audio-Magnetotelluric (AMT) Model in Nyalindung, Sukabumi–Indonesia

Cited by 11 publications

References 29 publications

Active Back‐Arc Thrust in North West Java, Indonesia

Active Back‐Arc Thrust in North West Java, Indonesia

Magnetotellurics (MT) and Gravity Study of a Possible Active Fault in Southern Garut, West Java, Indonesia

Integrated Magnetotelluric (MT), Gravity and Seismic Study of Lower Kutai Basin Configuration

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