scholarly journals Identifikasi Deformasi Tektonik Aktif Berdasarkan Ekstraksi Kelurusan Morfologi dan Seismisitas di Sukabumi, Jawa Barat

EKSPLORIUM ◽  
2021 ◽  
Vol 42 (1) ◽  
pp. 31
Author(s):  
Rizqi Muhammad Mahbub ◽  
Candra Ragil

ABSTRAK Pusat gempa bumi di Sukabumi telah membentuk deformasi bawah permukaan dan kini terekam juga di permukaan. Hal itu termanifestasi melalui geomorfologi kelurusan gawir dan sungai. Ekstraksi kelurusan-kelurusan akibat deformasi geologi tersebut dapat digunakan untuk mengidentifikasi deformasi tektonik aktifnya. Tujuan penelitian ini adalah untuk mengetahui hubungan antara struktur sesar aktif dengan arah dominan kelurusan di daerah penelitian. Metode Edge Enhancing Filtering digunakan untuk menginterpretasi kelurusan secara manual dan semi-otomatis. Data geospasial kelurusan diekstraksi menggunakan formula Sastratenaya untuk mengetahui kronologi kelurusan yang terbentuk. Hasil analisis menggunakan formula Sastratenaya menunjukkan kelurusan-kelurusan yang terekam melalui olah data peta DEM, yaitu segmen 1 berarah N315°E dan segmen 2 berarah N10°E yang diinterpretasikan sebagai hasil reaktivasi sesar. Hal ini dapat diinterpretasikan bahwa Sesar Cimandiri, yang merupakan sesar aktif dengan pergerakan oblique-slip sinistral N88°E/85° rake 33°, memengaruhi arah dua segmen kelurusan di daerah penelitian wilayah Sukabumi, Jawa Barat.ABSTRACT The epicenter of the earthquake in Sukabumi has formed subsurface deformation which is now also recorded on the surface area. This is manifested through the geomorphology of the scarp and river lineaments. Extraction of lineaments produced by geological deformation can be used to identify its active tectonic deformation. The research objective is to determine the relationship between the active fault structure and the dominant direction of lineaments in the study area. The Edge Enhancing Filtering method is used to interpret lineaments manually and semi-automatically. The lineament geospatial data was extracted using the Sastratenaya formula to determine the chronology of the lineaments formed. The Sastratenaya formula results showed the lineaments recorded by DEM images data processing, the first segment direction is N315°E and the second is N10°E, both are interpreted as the result of fault reactivation. It can be interpreted that the Cimandiri Fault, which is an active fault that has an N88°E/85° rake 33° sinistral oblique-slip fault movement, affects the lineaments direction of two segments in the research area of Sukabumi, West Java.

Geology ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 30-34
Author(s):  
Heather M. Kirkpatrick ◽  
Seulgi Moon ◽  
An Yin ◽  
T. Mark Harrison

Abstract Tectonic deformation can influence spatiotemporal patterns of erosion by changing both base level and the mechanical state of bedrock. Although base-level change and the resulting erosion are well understood, the impact of tectonic damage on bedrock erodibility has rarely been quantified. Eastern Tibet, a tectonically active region with diverse lithologies and multiple active fault zones, provides a suitable field site to understand how tectonic deformation controls erosion and topography. In this study, we quantified erosion coefficients using the relationship between millennial erosion rates and the corresponding channel steepness. Our work shows a twofold increase in erosion coefficients between basins within 15 km of major faults compared to those beyond 15 km, suggesting that tectonic deformation through seismic shaking and rock damage significantly affects eastern Tibet erosion and topography. This work demonstrates a field-based, quantitative relationship between rock erodibility and fault damage, which has important implications for improving landscape evolution models.


2019 ◽  
Vol 93 (3) ◽  
pp. 331-342
Author(s):  
Ahsan ul Haq ◽  
S. K. Pandita ◽  
Yudhbir Singh ◽  
G. M. Bhat ◽  
Shiv Jyoti Pandey ◽  
...  

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1127-1130 ◽  
Author(s):  
Gabriel G. Meyer ◽  
Nicolas Brantut ◽  
Thomas M. Mitchell ◽  
Philip G. Meredith

Abstract The so-called “brittle-ductile transition” is thought to be the strongest part of the lithosphere, and defines the lower limit of the seismogenic zone. It is characterized not only by a transition from localized to distributed (ductile) deformation, but also by a gradual change in microscale deformation mechanism, from microcracking to crystal plasticity. These two transitions can occur separately under different conditions. The threshold conditions bounding the transitions are expected to control how deformation is partitioned between localized fault slip and bulk ductile deformation. Here, we report results from triaxial deformation experiments on pre-faulted cores of Carrara marble over a range of confining pressures, and determine the relative partitioning of the total deformation between bulk strain and on-fault slip. We find that the transition initiates when fault strength (σf) exceeds the yield stress (σy) of the bulk rock, and terminates when it exceeds its ductile flow stress (σflow). In this domain, yield in the bulk rock occurs first, and fault slip is reactivated as a result of bulk strain hardening. The contribution of fault slip to the total deformation is proportional to the ratio (σf − σy)/(σflow − σy). We propose an updated crustal strength profile extending the localized-ductile transition toward shallower regions where the strength of the crust would be limited by fault friction, but significant proportions of tectonic deformation could be accommodated simultaneously by distributed ductile flow.


Author(s):  
Ajeng Sekarkirana Pramesti Kameswara ◽  
Nana Sulaksana ◽  
Murni Sulastri ◽  
P. P. Raditya R.

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.


2020 ◽  
Vol 90 (11) ◽  
pp. 1581-1600
Author(s):  
Luke A. Pettinga ◽  
Zane R. Jobe

ABSTRACT Submarine landscapes, like their terrestrial counterparts, are sculpted by autogenic sedimentary processes toward morphologies at equilibrium with their allogenic controls. While submarine channels and nearby, inter-channel continental-margin areas share boundary conditions (e.g., terrestrial sediment supply, tectonic deformation), there are significant differences between the style, recurrence, and magnitude of their respective autogenic sedimentary processes. We predict that these process-based differences affect the rates of geomorphic change and equilibrium (i.e., graded) morphologies of submarine-channel and continental-margin longitudinal profiles. To gain insight into this proposed relationship, we document, classify (using machine learning), and analyze longitudinal profiles from 50 siliciclastic continental margins and associated submarine channels which represent a range of sediment-supply regimes and tectonic settings. These profiles tend to evolve toward smooth, lower-gradient longitudinal profiles, and we created a “smoothness” metric as a proxy for the relative maturity of these profiles toward the idealized equilibrium profile. Generally, higher smoothness values occur in systems with larger sediment supply, and the smoothness of channels typically exceeds that of the associated continental margin. We propose that the high rates of erosion, bypass, and deposition via sediment gravity flows act to smooth and mature channel profiles more rapidly than the surrounding continental margin, which is dominated by less-energetic diffusive sedimentary processes. Additionally, tectonic deformation will act to reduce the smoothness of these longitudinal profiles. Importantly, the relationship between total sediment supply and the difference between smoothness values of associated continental margins and submarine channels (the “smoothness Δ”) follows separate trends in passive and active tectonic settings, which we attribute to the variability in relative rates of smoothness development between channelized and inter-channel environments in the presence or absence of tectonic deformation. We propose two endmember pathways by which continental margins and submarine channels coevolve towards their respective equilibrium profiles with increased sediment supply: 1) Coupled Evolution Model (common in passive tectonic settings), in which the smoothness Δ increases only slightly before remaining static, and 2) Decoupled Evolution Model (common in active tectonic settings), in which the smoothness Δ increases more rapidly and to a greater final value. Our analysis indicates that the interaction of the allogenic factors of sediment supply and tectonic deformation with the autogenic sedimentary processes characteristic of channelized and inter-channel areas of the continental margin may account for much of the variability between coevolution pathways and depositional architectures.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kongning Li ◽  
Deng Wu ◽  
Xi Chen ◽  
Ting Zhang ◽  
Lu Zhang ◽  
...  

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.


2021 ◽  
Author(s):  
Marianne Métois ◽  
Jean-Emmanuel Martelat ◽  
Jérémy Billant ◽  
Muriel Andreani ◽  
Javier Escartin ◽  
...  

Abstract. We present the content and scripting of an active tectonic lab-session conceived for third year undergraduate students studying Earth Sciences at Observatoire des Sciences de l’Univers of Lyon. This session is based on a research project conducted on the submarine Roseau active fault in Lesser Antilles. The fault morphology is particularly interesting to map as this structure in the deep ocean is preserved from weathering. Thus high resolution models computed from Remotely Operated Vehicle videos (ROV) provide exceptional educational material to link fault morphology and coseismic displacement. This5class, composed of mapping exercises on GIS and virtual fieldwork, aims at providing basic understanding of active tectonics,and in particular active fault morphology. The work has been conducted either in a full remote configuration via 3D online models or in virtual reality (VR) in a dedicated room using the Minerve software. During the VR sessions, students were either alone in the virtual environment or participated as a full group, including the teacher (physically in the classroom or remotely, from another location), which is to our knowledge one of the first attempts of this kind in France. We discuss on the efficiency10of virtual fieldwork using VR based on feedback from teachers and students, and we conclude that VR is a promising tool to learn observational skills, subject to certain improvements which should be possible in the years to come.


Author(s):  
M. Clementi ◽  
E. Labrozzi

Abstract. How can FOSS GIS support generative economy processes in small settled communities? The paper answers this question by proposing a toolbox made up of specific open geospatial data that can be processed through FOSS GIS. These data consist of specific maps, accompanied by numerical values.The information collected is intended to lay the foundations for an open-access manual of procedures to support the creation of an open database. This manual, currently under development, is created within a research funded by the Department of Architecture and Urban Studies of the Politecnico di Milano and is an integral part of an experimental game aimed at supporting students in the development of local self-sustainability scenarios.The manual is called the GED Toolkit. The acronym GED stands for Generative Environmental Design, with this term we refer to an approach to the design of the anthropized environment oriented towards the development of generative economies.The paper presents good practices, measuring their consistency with Generative Economy Principles through resource and impacts mapping. These are useful in the first place to understand the systemic features of the practice itself and the relationship with the territory that hosts it, and secondly to verify the possible transferability to other contexts.


1973 ◽  
Vol 63 (1) ◽  
pp. 211-225
Author(s):  
F. Richard Yeatts

abstract The static displacement field in an elastic half-space caused by a general, finite disturbance is derived in the form of an infinite series (multipole) expansion. The relationship between this theory and dislocation theory is discussed with the aid of examples. A multipole source model is derived for the strain-step field associated with the nuclear blast HANDLEY set off at the Nevada Test Site on March 26, 1970. The results suggest that there was significant fault movement associated with the detonation.


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