scholarly journals Earthquake Swarm Analysis around Mt. Salak, West Java, Indonesia, Using BMKG Data from August 10 to November 24, 2019

2021 ◽  
Vol 873 (1) ◽  
pp. 012002
Author(s):  
Pepen Supendi ◽  
Nanang T. Puspito ◽  
Andri Dian Nugraha ◽  
Sri Widiyantoro ◽  
Chalid Idham Abdullah ◽  
...  
Keyword(s):  
Earthquake Swarm ◽  
Tectonic Activity ◽  
Double Difference ◽  
Volcanic Area ◽  
Regional Network ◽  
Local Magnitude ◽  
West Java ◽  
Thrust Faulting ◽  
Time Period ◽  
Active Tectonic

Abstract Earthquake swarms commonly come approximately active tectonic and volcanic area. Interestingly, the swarm events occurred ~23 km southwest from Mt. Salak-Bogor, West Java, Indonesia, from August 10 to November 24, 2019, and were recorded by local/regional network of the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). Our previous study showed that in this area a destructive ML 4.6 earthquake with thrust faulting occurred on September 8, 2012. The double-difference method was applied to update the hypocenter locations from the BMKG data. In the time period of ~3.5 months, we relocated 79 swarm events with ~9.4 km depth average for local magnitude (ML) 2.2 to 4.2. The source mechanism result for selected events shows a strike-slip faulting. Our interpretation is that these swarm events are probably related to stress change due to volcano-tectonic activity.

Geomorphic Indexes of Tectonic Activity Relative through The Analysis Quantitative in Cisanggarung Watershed, Kuningan District, West Java, Indonesia

2021 ◽  
pp. 367-375
Author(s):  
Ajeng Sekarkirana Pramesti Kameswara ◽  
Nana Sulaksana ◽  
Murni Sulastri ◽  
P. P. Raditya R.
Keyword(s):  
Activity Index ◽  
Shape Index ◽  
Research Area ◽  
Tectonic Activity ◽  
West Java ◽  
High Class ◽  
Watershed Area ◽  
Average Value ◽  
Active Tectonic ◽  
Class 1

The research area is very interesting to study to determine the characterization of the active tectonic influence of the Cisanggarung watershed, West Java. The research area is in Kuningan Regency, West Java. The purpose of this study was to determine the Relative Tectonic Activity Index (Iatr) in the Cisanggarung Watershed. Through the method approach used to identify the Relative Tectonic Activity Index (Iatr) using geomorphic indexes, watershed asymmetry factors (Af), watershed shape index (Bs), valley width, and height valley ratio (Vf), and mountainous face sinusitis (Smf). The Iatr research area is divided into 4 classes: Class 1 (very high), class 2 (high), class 3 (medium), and class 4 (low). Iatr distribution in 14 sub-watersheds covering an area of 286.24 km2 is Class 1 around 14.44% of the watershed area (41.35 km2) which is located in sub-watershed 1, with Smf values 1.157, Vf 0.3, Af 72.15, and Bs 4.3. Class 2 around 28.67% of the watershed area (82.09 km2) is located in sub-watershed 14, with Smf values 1.26, Vf 0.77, Af 15.69, Bs 1.01. Class 3 around 54.16% of the watershed area (155.03 km2) is located in sub-watersheds 2, 3, 6, 7, 8, 10, 11, 12, with an average value of Smf 2, Vf 1.54, Af 51.77, Bs 1.75, and Class 4 about 2.71% of the watershed area (7.76 km2) is located in sub- watersheds 4, 5, 9, 13, with an average value of Smf 2.25, Vf 8.18, Af 55.2, Bs 1.65. The results of the morphometric analysis indicated that the study area was mostly affected by tectonics and erosion.

scholarly journals Late Miocene to Pliocene Tsunami Deposits in Tegal Buleud, South Sukabumi, West Java, Indonesia

2019 ◽  
Vol 13 (12) ◽  
pp. 80
Author(s):  
Yan Rizal ◽  
Aswan Aswan ◽  
Jahdi Zaim ◽  
Mika R. Puspaningrum ◽  
Wahyu D. Santoso ◽  
...  
Keyword(s):  
Late Miocene ◽  
Flame Structure ◽  
Tectonic Activity ◽  
Tsunami Deposit ◽  
Size Distributions ◽  
Volcanic Island ◽  
Tsunami Deposits ◽  
West Java ◽  
Foraminiferal Assemblage ◽  
Grain Size Distributions

Java is a volcanic island arc formed by the northwards subduction of the Eurasian and Australian Plates. Due to this active subduction, Java has been frequently shocked by earthquakes, which might induce tsunami events. However, there are hardly any ancient geological records of tsunami events in the area. This study aims to determine the presence and to identify sedimentary characters of tsunami deposit in Tegal Buleud, South Sukabumi, West Java. In the study area, there were 4 tsunami layers which were found as thin intercalation within the claystone layer of the Bentang Formation. Those paleotsunami deposits characterized by the occurrence of irregular/disturbed structure such as siltstone rip up, clay clasts, and flame structure occur in normal graded bedding sandstone layer. The grain-size distributions show bimodal and multimodal patterns, with mixing of marine microfossils from inner and middle neritic. The planktonic foraminiferal assemblage indicates that the age of the sediment comparable to N19 (equivalent to Late Miocene - Early Pliocene, at about 5.33 – 3.6 Ma), suggested that these paleotsunami layers were deposited due to the Mio-Pliocene tectonic activity. All the paleotsunami deposits found in Study area are the first and oldest tsunami deposit recorded in Java even in Indonesia. With the discovery of the previously unexplored Late Miocene to Pliocene tsunami deposits found in the study area, the result of this study can be used as a reference for the identification of the Tertiary tsunami deposits present in other parts of Indonesia.

scholarly journals MORPHOTECTONIC EVALUATION OF SIRCH MOUNTAINS USING WATER BASIN GEOMORPHIC INDICES

2021 ◽  
Vol 13 (2) ◽  
pp. 208-214
Author(s):  
Nafise HOSEINI ◽  
◽  
Shahram BAFTI ◽  
Reza DERAKHSHANI ◽  
Mohammad GHANBARIAN ◽  
...  
Keyword(s):  
Information System ◽  
Form Factor ◽  
Geographical Information System ◽  
Active Tectonics ◽  
Geographical Information ◽  
Tectonic Activity ◽  
Mountainous Region ◽  
Large Area ◽  
Active Tectonic ◽  
Morphotectonic Indices

Morphotectonic indices are useful instruments for investigating the effect of tectonic activity in a certain region. Calculation of these indicators using the advantages of Geographical Information System, GIS, in a large area is useful for detecting potential disorders related to active tectonics. This method is useful in regions on which few morphotectonic studies have been conducted. An example of such areas can be the watersheds of the Sirch mountainous region. The watersheds of the Sirch region located in Central Iran’s zone in the southeast of Iran are a very ideal zone to evaluate the concepts of these indicators in the prediction of the relative tectonic activity according to the investigation of drainage systems or mountain fronts. Based on the values of the calculated indices including Form Factor (FF), Compaction Coefficient (CC), Ratio of Circularity (RC), Ratio of Elongation (RE), relative Basin Height (BH), and Ruggedness Number (RN), a final indicator called Active Tectonic Indicator (ATI) is obtained. The latter is a combination of the abovementioned indicators and evaluates the morphotectonic activity based on the shape of the watersheds. By measuring and combining these indicators, the tectonic activity stage of the Sirch region was determined by analyzing the watersheds of this region.

scholarly journals An intraplate slow earthquake observed by a dense GPS network in Hokkaido, northernmost Japan

2014 ◽  
Vol 200 (1) ◽  
pp. 144-148 ◽  
Author(s):  
Mako Ohzono ◽  
Hiroaki Takahashi ◽  
Masayoshi Ichiyanagi
Keyword(s):  
Subduction Zones ◽  
Earthquake Swarm ◽  
Tectonic Activity ◽  
Maximum Magnitude ◽  
Slow Slip ◽  
Localized Deformation ◽  
Slow Earthquake ◽  
Magnitude Scaling ◽  
Duration Magnitude ◽  
Slow Earthquakes

Abstract An intraplate slow earthquake was detected in northernmost Hokkaido, Japan, by a dense network of the global navigation satellite system. Transient abnormal acceleration of <12 mm was observed during the period 2012 July to 2013 January (∼5.5 months) at several sites. The spatial displacement distribution suggests that a localized tectonic event caused localized deformation. Estimated fault parameter indicates very shallow-dip reverse faulting in the uppermost crust, with a total seismic moment of 1.75E + 17 N m (Mw 5.4). This fault geometry is probably consistent with detachment structure indicated by geological studies. A simultaneous earthquake swarm with the maximum magnitude M4.1 suggests a possibility that the slow slip triggered the seismic activity for unknown reasons. This slow earthquake is slower than its moment would indicate, with a duration–magnitude scaling relationship unlike either regular earthquakes or subduction slow slip events. This result indicates that even if the area is under different physical property from subduction zones, slow earthquake can occur by some causes. Slow earthquakes exist in remote regions away from subduction zones and might play an important role in strain release and tectonic activity.

scholarly journals FEATURES OF TECTONIC DEVELOPMENT OF STRUCTURES IN THE MIDDLE OB BY CORRELATION OF THICKNESS ANALYSIS

2018 ◽  
pp. 77-83
Author(s):  
F. Z. Khafizov
Keyword(s):  
Correlation Analysis ◽  
Middle Jurassic ◽  
Large Scale ◽  
Upper Cretaceous ◽  
Tectonic Activity ◽  
Active Tectonic ◽  
History Of ◽  
Tectonic Development

The article is devoted to the main patterns of tectonic development in the Middle Ob for the period from the tops of the middle Jurassic to the Eocene. It is shown that during this period of time in the tectonic development of the territory there were periods of quiet sedimentation and very active tectonic activity. In the history of the tectonic development of the Middle Ob four major stages are distinguished: two is quiet (the Jurassic and the Upper Cretaceous) and two are very active with large-scale multidirectional movements that led to a significant increase in the amplitudes of the structures (from the Cretaceous to the roof of the Cenomanian century).The article describes the methodology of the correlation analysis used in the study of the history of tectonic development in the territory.

THE STATUS OF SOIL PHOSPHORUS AT DIFFERENT CROPPING SYSTEM IN PANGALENGAN, SOUTH BANDUNG

2019 ◽  
Vol 11 (2) ◽  
pp. 76-80
Author(s):  
Sri Djuniwati ◽  
Heru Bagus Pulunggono
Keyword(s):  
Organic Matter ◽  
Cropping System ◽  
Organic Content ◽  
Soil Samples ◽  
Soil Reaction ◽  
Volcanic Area ◽  
P Fractions ◽  
West Java ◽  
Humid Forest ◽  
P Fraction

The fixation of P in soils is dynamic in nature and the behavior of P-fraction may change with time and cropping system. Application of organic matter to soil under upland soil have been reported to decrease P-sorption and increase P-desorpion.  Pangalengan, South Bandung in west Java is one of the wet humid area of Indonesia that has high rain fall, covered mainly by tropical humid forest, volcanic area with fertile volcanic soil. The objective of this study were to describe and compare some chemical characteristic and behavior of P-fraction as a function of  crops and slope of the land in the farming system in Pangalengan, South Bandung, West Java, Indonesia. Soil samples from the surface soil (0-20 cm) were collected from 15 locations based on different planted crops (Tea, Vegetables, Forest, and Intercropping crops),  and level of slope of the land areas of Cihawuk village, District Kertasari, Kecamatan Pangalengan.  The result of the study showed that C-organic content of  soil samples from 15 location of planted crops was slightly high (3.04-4.92 %) but total Nitrogen was low (0.22-0.45 %), wih soil reaction (pH H2O) was  slightly acids (5.60-6.30) and pH (KCl) was lower than pH(H2O) (4.60-5.70).    The  available-P was low (3.50 – 7.10 ppm), but the HCl 25 % P　from  tea and vegetables  location was higher than from forest and intercropping crops.   Majority of P fraction  from tea and vegetable location was Al-P fraction, but from Forest and intercropping crops was  Ca-P fraction. The order of P fraction were Al-P > Ca-P> reductant soluble-P>Fe-P in tea and vegetables locations, but in the forest and intercropping were Ca-P> reductant-P > Al-P > Fe-P.  However, The data showed that the total P (P-organic + P-inorganic) from tea and vegetables crop location was higher, and was dominated by inorganic form, than from forest and intercropping location was dominated by organic form.  However, the slope did not affect the pattern of P-fractions and   the sources of organic matter added or accumulated in those location formerly  affected the amount and the pattern of P-fractions.

Velocity Structure of the Northeastern End of the Bayan Har Block, China, and the Seismogenic Environment of the Jiuzhaigou and Songpan-Pingwu Earthquakes: Inferences from Double-Difference Tomography

2021 ◽  
Author(s):  
Wen Yang ◽  
Zhifeng Ding ◽  
Jie Liu ◽  
Jia Cheng ◽  
Xuemei Zhang ◽  
...  
Keyword(s):  
Lower Crust ◽  
Velocity Structure ◽  
Joint Inversion ◽  
Earthquake Swarm ◽  
P Wave ◽  
Double Difference ◽  
The Tibetan Plateau ◽  
Upper Crust ◽  
Low Viscosity ◽  
Bayan Har

ABSTRACT The 2017 Mw 6.5 Jiuzhaigou mainshock hit the northeastern end of the Bayan Har block, which has experienced many historical earthquakes, including the 1976 M 7.2 Songpan-Pingwu earthquake swarm. We used the double-difference tomography method to perform a joint inversion of the seismic source and P-wave velocity (VP) structure of the Jiuzhaigou-Songpan-Pingwu region. The results show significant lateral heterogeneity in the VP in the mid-upper crust. The velocity structure in the shallow crust correlates well with the surface geology. The Jiuzhaigou mainshock and Songpan-Pingwu earthquake swarm both occurred at the boundary between high- and low-VP anomalies. The Songpan-Pingwu earthquake swarm may be related to the eastward flow of low-viscosity material in the mid-lower crust of the Tibetan plateau. Low-viscosity material intrudes into the bedrock when it encounters the rigid Motianling massif, resulting in surface uplift and thrust earthquakes. By contrast, the Jiuzhaigou earthquake is associated with strain energy accumulating at the boundary between high- and low-VP anomalies related to the different movement rates of the low-VP material in the mid-lower crust and the high-VP body in the mid-upper crust. In this case, the high-VP body ruptures with a strike-slip sense to the southeast.

The 2020 volcano-tectonic unrest at Reykjanes Peninsula, Iceland: stress triggering and reactivation of several volcanic systems

2021 ◽  
Author(s):  
Halldór Geirsson ◽  
Michelle Parks ◽  
Kristín Vogfjörd ◽  
Páll Einarsson ◽  
Freysteinn Sigmundsson ◽  
...  
Keyword(s):  
Earthquake Swarm ◽  
Plate Boundary ◽  
Tectonic Activity ◽  
Volcanic System ◽  
Multiple Systems ◽  
The North ◽  
Stress Changes ◽  
Uplift Rates ◽  
Source Models ◽  
Reykjanes Peninsula

<p>The Reykjanes Peninsula in south-west Iceland straddles the North-America - Eurasia plate boundary and hosts several active volcanic systems, including the Svartsengi volcanic system. The last eruption in this area took place around 1240 CE, with eruptive episodes recurring every 800-1000 years, affecting one volcanic system at a time, but spanning multiple systems  with activity spaced ~100 to 200 years. In January 2020, unrest was identified in Svartsengi, characterized by intense seismicity and inflation at a rate of 3-4 mm per day. This area is located within 5 km of several important infrastructures: a) the town of Grindavík; b) the Svartsengi geothermal power plant; c) and the Blue Lagoon geothermal spa, which had over a million annual visits before the Covid pandemy.</p><p> </p><p>Two continuously recording GNSS stations were installed in the Svartsengi geothermal area in 2013-2015 to monitor geothermally-induced subsidence.  Coinciding with the onset of an earthquake swarm starting on January 21 (M<4), uplift of about 3-4 mm/day was noticed in automated GNSS and InSAR results. The uplift rates in this first inflation phase decreased after January 31 and reverted to slight subsidence in early February. Interestingly, the most intense seismicity was offset from the uplift center by about 2-4 km to the southeast. Geodetic source models from the initial two weeks indicate the deformation is the result of a sill intrusion at a depth of about 4 km  with a volume change of approximately 3  million m<sup>3</sup>. The resulting stress changes from this intrusion act to increase seismicity at the sill edges, thus offering an explanation for why the seismicity is offset from the center of uplift. The location of the sill coincides roughly with a crustal volume with a high V<sub>p</sub>/V<sub>s</sub> ratio.</p><p> </p><p>Two more inflation-deflation episodes have occurred at Svartsengi in 2020 and the total uplift amounts to approximately 12 cm. Additionally, at least one inflation episode occurred in the Reykjanes system, in February 2020, and inflation started in the Krýsuvík system in mid-July 2020, culminating in a M5.6 earthquake on October 20. The Fagradalsfjall system, between Krýsuvík and Svartsengi, has shown high seismicity in 2020, but does not display detectable inflation nor deflation. Therefore, the volcano-tectonic activity in 2020 spans the entire western part of the Reykjanes Peninsula. The stress changes for each of these events are too small to explain the cross-system activity, hence we suggest the entire unrest is  by deep magma migration beneath the entire western Reykjanes Peninsula.  </p>

Reservoir Induced Seismicity Types in the Three Gorges Project

2013 ◽  
Vol 838-841 ◽  
pp. 1508-1511 ◽  
Author(s):  
Li Fen Zhang ◽  
Jing Gang Li ◽  
Wu Lin Liao ◽  
Qiu Liang Wang
Keyword(s):  
Induced Seismicity ◽  
Earthquake Swarm ◽  
Active Faults ◽  
Rapid Response ◽  
Double Difference ◽  
Delayed Response ◽  
Three Gorges ◽  
Reservoir Induced Seismicity ◽  
The Three Gorges ◽  
Water Impoundment

Reservoir Induced Seismicity(RIS) is a common phenomenon needed to be focused in the construction and operation of water conservancy project. The Three Gorges reservoir has a digital telemetry seismic network to monitor the earthquakes in this region. According to the correlation between water impoundment and earthquakes, the reservoir induced seismicity can be divided into rapid response and delayed response. The two types can be found in the Three Gorges area as well. In 2003, soon after the first stage of water impoundment, micro earthquake swarm occurred, which is so called rapid response type and water loading is the main factor. And delayed effect is the most observed phenomenon in RIS, in which pore diffusion controls the earthquakes. Double difference relocation results show that the earthquakes can be generally divided into three regions. And the earthquakes controlled by the active faults are called tectonic type RIS, while those related with karst, landslide, etc are nontectonic type. In region A, some earthquakes are related with the Gaoqiao active fault, and some have relationship with karst. The earthquakes in region B are controlled by some coalmines, landslide, and so on. And the earthquakes in region C belong to tectonic type RIS, which have certain relationship with the Xiannvshan fault and Jiuwanxi fault. Different RIS types have different mechanisms and controlling factors, furthermore have different earthquake trending.

From earthquake swarm to a main shock–aftershocks: the 2018 activity in West Bohemia/Vogtland

2020 ◽  
Vol 224 (3) ◽  
pp. 1835-1848
Author(s):  
M Bachura ◽  
T Fischer ◽  
J Doubravová ◽  
J Horálek
Keyword(s):  
Main Shock ◽  
Fault Plane ◽  
Earthquake Swarm ◽  
Seismic Energy ◽  
Aftershock Sequence ◽  
Double Difference ◽  
Differential Stress ◽  
West Bohemia ◽  
Spatio Temporal ◽  
Insight Into

SUMMARY In earthquake swarms, seismic energy is released gradually by many earthquakes without a dominant event, which offers detailed insight into the processes on activated faults. The swarm of May 2018 that occurred in West Bohemia/Vogtland region included more than 4000 earthquakes with ML =〈0.5, 3.8&x3009 x232A;and its character showed significant changes during the two weeks duration: what started as a pure earthquake swarm ended as a typical main shock–aftershock sequence. Based on precise double-difference relocations, four fault segments differing in strikes and dips were identified with similar dimensions. First, two segments of typical earthquake swarm character took place, and at the end a fault segment hosting a main shock–aftershock sequence was activated. The differences were observable in the earthquakes spatio-temporal evolutions (systematic versus disordered migration of the hypocentres), b-values (>1.3 for the swarm, <1 for the main shock–aftershocks), or the smoothness of seismic moment spatial distribution along the fault plane. Our findings can be interpreted by local variations of fault rheology, differential stress and/or smoothness of the faults surface, possibly related to the crustal fluids circulating along the fault plane and their interplay with the seismic cycle.

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