Crustal shear-wave velocity structure beneath Sumatra from receiver function modeling

Bora, Dipok K.; Borah, Kajaljyoti; Goyal, Ayush

doi:10.1016/j.jseaes.2016.03.007

Cited by 29 publications

(16 citation statements)

References 34 publications

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“…At this depth, the Vs is ∼3.3 km/s on average. In comparison, the Vs model that was also derived from a RF study for the BKNI station (Bora et al, 2016) located ∼100 km northeast of Marapi, shows a shear wave speed of 3.4-3.8 km/s at the same depth. The land stations across Sumatra revealed Vs in the range of 3.4-3.6 km/s (Harmon et al, 2012) and the global crust model CRUST 1.0 (Laske et al, 2013) provides a Vs of 3.62 km/s for the middle crust in the studied area.…”

Section: Magma Storage Location and Reservoir Characteristicsmentioning

confidence: 91%

Combining Petrology and Seismology to Unravel the Plumbing System of a Typical Arc Volcano: An Example From Marapi, West Sumatra, Indonesia

Nurfiani

Wang

Gunawan³

et al. 2021

Geochem Geophys Geosyst

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Marapi in Sumatra is characterized by frequent short‐lived explosions and small eruptions (Volcanic Explosivity Index 1–2) and in the past 250 years, the volcano has erupted >60 times. Recent volcanic bombs and the presence of broadband seismic stations lead us to reconstruct the plumbing system of the volcano through an interdisciplinary study. A petrologic study of the summit bombs uses pyroxene, plagioclase and glass compositions to obtain pressures and temperatures of magma storage as well as identify pre‐eruptive processes. Two‐pyroxene geothermobarometry provides pre‐eruptive crystallization pressure estimates of 4–7 kbar (∼15–26 km). Compositional and textural analyses of plagioclase and pyroxene crystals indicate that mafic magma recharge was followed by mixing with the resident magma and renewed crystallization prior to eruption. In order to further image the magma reservoir, we performed a joint inversion of teleseismic receiver functions and surface waves (H/V ratio). The inversion reveals a low velocity zone (LVZ) at depths of 15–21 km that has 7 ± 3% shear velocity reduction, corresponding to an estimated melt fraction of 5 ± 2%. The depth of this LVZ overlaps with the depth of magma storage estimated from petrology, constraining it with high confidence. Such a combined interdisciplinary study provides valuable information for evaluating future periods of unrest, laying out a framework for the interpretation of incoming monitoring data and signals to look out for in order to improve eruption forecasts.

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Section: Magma Storage Location and Reservoir Characteristicsmentioning

confidence: 91%

Combining Petrology and Seismology to Unravel the Plumbing System of a Typical Arc Volcano: An Example From Marapi, West Sumatra, Indonesia

Nurfiani

Wang

Gunawan³

et al. 2021

Geochem Geophys Geosyst

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“…The Barisan Mountain was formed from tectonic activity which caused all sedimentary rock to fold and grow strongly, followed by volcanism allowing the bedrock to be lifted to the surface. Macpherson et al (2012) and Bora et al (2016) believed that the HVL under the BKNI station is due to a layer of sedimentary rock overlapping the bedrock in the back-arc basin area. From geological information, the rock characters scattered on the island of Sumatera are volcanic, including the igneous rock type consisting of andesite and diorite found in Lampung (Indarto et al, 2008).…”

Section: High Velocity Layermentioning

confidence: 99%

“…Western and Eastern Indonesia are separated by the islands of Kalimantan and Sulawesi with a complex structure, which is also a transitional area between the peculiarities of the geological features of the Asian and the Australian continent. Previous studies on crustal structure have been carried out in Indonesia using the receiver function method, including in the island of Sumatera, where the thickness of the earth's crust varies from 16 km to 40 km (Kieling et al, 2011;Macpherson et al, 2012;Bora et al, 2016). Other researchers performed the receiver function study in the island of Java where the thickness of the crust in the western part of the island was 25-37 km (Syuhada and Anggono, 2016; Anggono et al, 2020), in the central and east part of Java island about 25-39 km (Wölbern and Rümpker, 2016;Amukti et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Sediment Thickness and Moho Depth Beneath Western Indonesian Region From Teleseismic Receiver Function

Bahri

Suryanto

Ngadmanto

2021

Preprint

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The Earth's crust layer and sediment in Western Indonesia has been studied using the inversion of teleseismic receiver function from BMKG’s seismic network. Earthquake events were analyzed in this study with a moment magnitude greater than 6.0 with epicentral distances of 30° to 90°. A total of 60 earthquake events were observed and recorded by 91 stations around the study area. Furthermore, an inversion process was carried out using the initial velocity model from the modification of the AK135f velocity model to obtain the shear wave velocity structure below each stations. The velocity model from the azimuthally stacked vertical receiver function showed that the sediment layer had a relatively medium shear wave velocity value with an average of 2.1 km/s, while the crust layer had 4.60 km/s. The sedimentary layer thickness in this region also varies between 2 km to 10 km. A relatively thick sediment layer of about 8 km to 10 km was observed in two locations, in East Kalimantan associated with the Kutai Basin and Northern part of Sumatera in the North Sumatera Basin, a two major oil producer basinal area in Indonesia. The Moho discontinuity was also found at depths that vary between 16 km to 50 km. In addition, the most shallow Moho depth is 16 km below the North Kalimantan and North part of West Java, while the deeper Moho depth of 50 km is located below East Kalimantan, Central Kalimantan, North Sumatera and South Sumatera.

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“…According to previous research, the crust thickness of Sumatra varies from 27-35 km (Bora et al, 2016).…”

Section: Regional Heat Flowmentioning

confidence: 93%

The Potential of Sukadana Basalt Province as a New Geothermal Resources in The Back Arc of Sumatra

Siringoringo

Sipayung

2023

IJE

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Geothermal resources are currently obtained from areas within volcanic arcs, such as the Pertamina Ulu Belu and Supreme Energy Rajabasa Geothermal Fields. However, this understanding may change in the future, as the Quaternary Sukadana Basalt Province (SBP), located in the back arc, is believed to have potential as a future geothermal energy resource. This research aims to explore the various factors that contribute to the high heat flow in the SBP region and generate a new perspective on geothermal energy particularly in the Lampung province. The methods used integrate previous research findings, such as heat flow data, regional tectonics, and geological structures, with new petrography-whole rock geochemistry. The whole rock geochemistry was determined using X-Ray Fluorescence (XRF), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The SBP was formed by the Paleogene northwest-southeast striking fault and influenced by the Quaternary northeast-southwest striking fault, which may serve as conduits for hydrothermal fluid in addition to their vesicular structures. Geochemical analysis suggests the presence of both mantle plume and subduction-related processes. The magmatism linked to subduction-plume tectonic mechanisms and the thinning of the crust due to pull-apart motion caused by the movement of two large faults (Sumatra Fault Zone and Bangka Shear) can increase regional heat flow to 100±10 mW/m2. As a result, the SBP has significant potential as a source of geothermal energy for electricity generation in the future.

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Crustal shear-wave velocity structure beneath Sumatra from receiver function modeling

Cited by 29 publications

References 34 publications

Combining Petrology and Seismology to Unravel the Plumbing System of a Typical Arc Volcano: An Example From Marapi, West Sumatra, Indonesia

Combining Petrology and Seismology to Unravel the Plumbing System of a Typical Arc Volcano: An Example From Marapi, West Sumatra, Indonesia

Sediment Thickness and Moho Depth Beneath Western Indonesian Region From Teleseismic Receiver Function

The Potential of Sukadana Basalt Province as a New Geothermal Resources in The Back Arc of Sumatra

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