Muksin Umar - Academia.edu (original) (raw)

Papers by Muksin Umar

Jurnal Arsip Rekayasa Sipil dan Perencanaan

Journal of Physics: Conference Series, 2021

The rheology of a material especially related to mechanical behaviour is an important characteris... more The rheology of a material especially related to mechanical behaviour is an important characteristic. Rheology has wide applications for example in nanomaterials, engineering design, biology, and in a large scale case in geodynamics study. Rheology relies on several physical equations such as continuity equation, momentum equation, gravity potential, state equation, heat transfer, and advection equation. The equations seem to be simple, however, the application of those equations to a real case is not easy and causes many numerical problems. Marker-in-Cell (MIC) is a technique to solve a numerical rheology modelling problem especially diffusion of sharp gradients during the advection process. The technique successfully simulates the advection process for thermomechanical viscous material for a 2-dimensional case study. The model was initially set up two parts with laterally contrast difference of material characteristics. The lateral density difference of material induced gravitatio...

International Journal of Renewable Energy Development, 2020

Remote sensing makes it possible to map potential geothermal site for a large area effectively us... more Remote sensing makes it possible to map potential geothermal site for a large area effectively using thermal infrared. The purpose of the present research is to overlay ground temperature, resistivity and satellite retrieved temperature in identifying geothermal potential site in Jaboi, Sabang-Indonesia. The data of acquisition of the DEM imagery was January 3rd, 2009 and the Landsat 8 imagery is July 18th, 2017. The satellite data were applied to extract the land surface temperature and land classification across. Two supporting data in situ were used to validate the results from remote sensing. First dataset was ground temperature measurements with total 114 points and second dataset was vertical electrical sounding (VES) with total of 51 points. Satellite, VES and ground temperature data were processed and analysed using the Envi 5.3, PCI Geomatica 2016 and ArcMap 10.4. The results from each data were integrated to produce a map shows geothermal potential. Its integration produce...

International Journal of Disaster Risk Reduction, 2019

, a series of field surveys were performed to further understand the impacts of the resulting tsu... more , a series of field surveys were performed to further understand the impacts of the resulting tsunami. Tsunamis initiated by strike-slip earthquakes are rare. Other factors are suspected to have contributed to this unusual tsunami. One of these factors was the subaerial landslides around Palu Bay, which were observed at several locations. This paper aims to investigate the characteristics of the tsunami based on the flow depths/heights, tsunami inundation, wave direction and tsunami debris. The surveys were performed from 12 October to 10 November in 2018. The flow depths were measured at 84 locations along the bay. Higher tsunami depths were found at Talise Beach, which is on the closed end of the bay. The southwestern edge of Palu Bay had lower tsunami depths compared to the northeastern edge. The highest flow depth measured in this study was at the village of Tondo, at the northeastern edge of the bay. The sporadic subaerial landslides that generated the tsunami were implicated by the direction of the tsunami waves, which were inconsistent with nearby data. The combination of the complicated tsunami characteristics and the minimum level of tsunami mitigation contributed to the large number of casualties during the 2018 Palu Bay tsunami.

Jurnal Natural, 2017

Climate change is a global phenomenon that currently and seriously impacts the environment. Incre... more Climate change is a global phenomenon that currently and seriously impacts the environment. Increasing concentrations of greenhouse gases have caused changes in extreme climate events. We have studied index rainfall extream trend at two meteorological stations of Sultan Iskandar Muda in Banda Aceh and Cut Nyak Dien in Meulaboh from 1982-2013. Daily rainfall data were processed using software of RClimDex to obtain the extreme rainfall index. Such indexes are extreme climate index set by the expert team for Climate Change Detection Monitoring and Indices (ETCCDMI) including of maximum 1-day and 5-days precipitation amount (RX1day and RX5day), total annual precipitation (PRCPTOT), consecutive dry days (CDD), consecutive wet days (CWD), very wet days (R95p), extremely wet days (R99p) and heavy precipitation days (R20mm). Based on our study, we found that the PRCPTOT tend to decrease, whereas occurances of RX1day and RX5day increase. The Banda Aceh station which has a monsoonal pattern is charaterized by increasing in R95p and R99p as well as but decreasing in R20mm. The CWD and CDD tend to accumulate at once. The Meulaboh station that has the type of equatorial rain show decreasing trend in R95p and R99p, but increasing trend in R20mm. The CWD and CDD occur within some days. The projection Representative Concentration Pathways (RCP) 4.5 and 8.5 from 2014-2050 showed an increasing pattern frequency of rain in Banda Aceh and a decreasing pattern in Meulaboh.

Journal of Volcanology and Geothermal Research, 2013

A passive seismic experiment with 42 short-period stations was setup for 10 months from May 2011 ... more A passive seismic experiment with 42 short-period stations was setup for 10 months from May 2011 within a 20-30 km radius covering the Tarutung basin and the northern part of the Sarulla graben along the seismically active Sumatran fault (North Sumatra, Indonesia). The objective of the project is to investigate the geothermal setting based on the Vp and Vp/Vs structures and the distribution of seismicity. We recorded 2856 local earthquakes by at least 8 stations which were reduced to 809 events having gap angle less than 180°. The initial earthquake locations were determined using simultaneous inversion for hypocenters and 1D velocity structure followed by 3D tomographic inversion. The resulting seismicity distribution, Vp and Vp/Vs structure reveal systematic differences between the Tarutung basin and the Sarulla graben. The Tarutung pull-apart basin is characterized by a complex structure reflected by a broader distribution of seismicity compared with the very narrow, rather vertical hypocenter distribution in the Sarulla graben, which was formed by fault-perpendicular extension and not by pull-apart tectonics. High Vp/Vs values near to the surface are imaged within the Sarulla graben and northeast of the Tarutung basin. These features are interpreted as fluid bearing sediments with fracturing indicating potentially favorable conditions for geothermal exploitation. The localized fluid flow northeast of Tarutung could be explained by the releasing step-over structure of the pull-apart basin and resulting dilatational stress regime in this part of the basin. Heat sources are assumed to be located at greater depth in association with magmatic activities accompanying the subduction process, and the heat is transported along the Sumatran fault to shallow depth.

Jurnal Lingkungan dan Bencana Geologi

ABSTRAK Banda Aceh dikategorikan sebagai kota besar yang rentan akan bahaya gempa bumi karena ter... more ABSTRAK Banda Aceh dikategorikan sebagai kota besar yang rentan akan bahaya gempa bumi karena terletak pada sistem tektonik aktif yaitu Patahan Sumatra yang tersegmentasi yaitu Seulimeum di bagian timur dan Aceh di bagian barat. Aktivitas kedua segmen yang membangkitkan kegempaan lokal dapat memberikan potensi kerusakan besar pada masa mendatang. Potensi tersebut dapat dipelajari dengan analisis kerentanan seismik berdasarkan parameter mikrotremor seperti nilai frekuensi (f0), amplifikasi (A), kerentanan seismik (Kg) dan kecepatan geser (Vs30). Dalam studi ini, kami melakukan survei mikrotremor Horizontal Vertical Spectral Ratio (HVSR) dan SPatial AutoCorrelation (SPAC) pada daerah Peukan Bada yang menjadi bagian Kota Banda Aceh. Sebanyak 19 titik HVSR dianalisis dengan perbandingan spektrum H/V dan 3 titik SPAC dianalisis dengan F-K analisis pada kurva dispersi gelombang rayleigh untuk mendaptkan nilai kecepatan geser pada kedalaman 30m (Vs 30). Hasil parameter yang diperoleh yaitu...

Elkawnie, 2021

The condition of stress and recent seismicity in the seismic-prone area can be statistically anal... more The condition of stress and recent seismicity in the seismic-prone area can be statistically analyzed with the Gutenberg-Richter relation. We apply this relation to the hypocenter distribution for the period 1970-2020 with M ≥ 4 and depth ≤ 200 km in the northern part of Sumatra. Spatially, The results obtained, a-values and b-values, figure a lateral heterogeneity and stress accumulation with dense structures at the interface zone in the subduction system and the northern segmentation of the Seulimeum fault. In time, both zones illustrate a slow time-to-failure cycle and seismic gap with high stress accumulation in the specific clusters with high seismic parameter values. The results of the spatial temporal analysis illustrate that each major earthquake event is usually preceded by a low statistical parameter value.

IOP Conference Series: Earth and Environmental Science, 2021

Tsunami warning is one of many important reports to save lives and reduce the damage for local pe... more Tsunami warning is one of many important reports to save lives and reduce the damage for local peoples. A moment magnitude of P-wave (Mwp) and the rupture time duration (Tdur) can be used as the quickly parameters to diseminate the tsunami warning. In this paper, we analyze the seismic waveform from global network to get Mwp and Tdur of South-West Coast of Sumatera earthquake. Mwp was calculated using automatic and manual phase picking of P phase. The results of this study show a well-analyzed relationship between P wave from automatic and manual picking, Mwp and time duration, respectively. The result also give an encouraging studies for the early warning system that will be set up in the future in the region.

Salah satu gempa bumi yang berdampak pada kerusakan rumah penduduk telah terjadi di Sumatra tepat... more Salah satu gempa bumi yang berdampak pada kerusakan rumah penduduk telah terjadi di Sumatra tepatnya adalah daerah Pidie Jaya pada tanggal 7 Desember 2016, sebesar Mw 6.5. Pada penelitian ini akan dilakukan analisa pada mekanisme fokal gempa bumi menggunakan inversi wavefom dari seismogram digital tiga komponen. Mekanisme fokal gempa bumi dimodelkan dari proses inversi tensor momen menggunakan program ISOLA. Hasil inversi tensor momen menunjukan bahwa gempa bumi Pidie Jaya merupakan gempa bumi dengan mekanisme sesar geser dengan bidang nodal 1; strike 254°, dip 80°, slip 48° dan bidang nodal 2; strike 153°, dip 42°, slip 165°. One of destructive earthquake that occurred in Sumatra region is Pidie Jaya earthquake, on the 7th of December, 2016 with Mw 6,5. The aim of this study is to analyze the focal mechanism using waveform inversion three component digital seismogram. Earthquake focal mechanism is determined by moment tensor inversion method using ISOLA program. Moment tensor inver...

We have deployed about 48 three component seismometers around "AFA" hydrothermal are in West Java... more We have deployed about 48 three component seismometers around "AFA" hydrothermal are in West Java, Indonesia from October 2012 up to October 2014 in order to detect microseismic event and to enhance our knowledge about subsurface seismic stucture. The seismometer network in this study, is the first dense seismometer array monitoring around hydrothermal area in Indonesia so far. We analyzed a huge waveform data set to distinguish microseismic, local and regional events. Then, we picked the onset of P-and S-wave arrival of microseismic events carefully visually by eye. We determined the initial microseismic event by applying Geiger's method with uniform seismic velocity model. Totally, we have been successfully determined 2,497 microseismic events around this hydrothermal area. We also improved 1D seismic velocities (Vp, Vs) and simultaneously with hypocenter adjustment as input for the tomography inversion in this study. Overall, the microseismic events are concentrated around production area activities and we also found strong cluster microseismic event in Southern part of this region which still need to be investigated in more details. Now, we are going on tomographic inversion step by using double-difference method. We are going to show more information during the meeting.

Elkawnie, 2020

Banda Aceh can be categorized as an earthquake-prone city because of the existence of two active ... more Banda Aceh can be categorized as an earthquake-prone city because of the existence of two active segments namely Seulimeum and Aceh. Both segments are considered to provide great potential damage in the future. In this article, we conduct a microtremor survey in the Peukan Bada, sub-part of Banda Aceh city, to learn the vulnerability level and support disaster mitigation plan. A total of 20 sites were measured with a seismometer to record the seismic waveform. The waveform was recorded in 45 minutes with a sampling rate of 100 sps and has analyzed using the horizontal-vertical spectrum ratio (HVSR). The results obtained are the dominant parameters, such as the period with a range of 0-0.5s, frequency with a range of 0-6 Hz, seismicity vulnerability index with a range of 0.1-0.5. The result was relevant to the geological conditions of Peukan Bada that dominated by alluvial rocks and mud sediments. The level of vulnerability (K g > 1.0) obtained is quite high and proportional to the soil type that can amplify the seismic waveform. The results obtained are expected to be a supporting study of disaster mitigation and understand the geological conditions of Banda Aceh in terms of seismic vulnerability.

Jurnal Geofisika, 2018

A signicant Mw 6.5 earthquake occurred in Pidie Jaya, Aceh on December 7th, 2016. The event affec... more A signicant Mw 6.5 earthquake occurred in Pidie Jaya, Aceh on December 7th, 2016. The event affected104 people death and more than 1000 people suered injuries due to the rubble of the building. Geologically, the region is composed by of Quaternary alluvial deposits. This is one of factor that amplication occurred in some area. On the other hand, an understanding of the source and mechanism of the earthquake needs to be done. A few days after the earthquake, we deployed 9 seismometers that covered the area of Pidie, Pidie Jaya and Bireuen. This experiment aims to record the aftershock and understanding of earthquake source and mechanism. In addition, we conducted building damage survey to know the pattern of distributionof building damage.

Seismological Research Letters, 2018

A total of 48 seismometers were deployed from October, 2012 to October 2013 around a geothermal f... more A total of 48 seismometers were deployed from October, 2012 to October 2013 around a geothermal field in the southern part of the Bandung basin region. A threshold time difference between S and P-wave was applied with an arrival time of less than three seconds. Otherwise, the waves were assumed as regional or teleseismic events. Then the P-and S-wave arrival times of events were carefully picked visually by eye. After this, the events were located. So far, 1,260 microearthquake events have been determined using a nonlinear algorithm integrated in the seismotool. These events seem to concentrated around geothermal field. Seismic velocities from the 1-D model were used as input for the 3-D seismic tomography inversion to invert for 3-D Vp, Vs, and Vp/Vs ratio subsurface structures around this geothermal field.

In order to improve our understanding and enhancing the knowledge about structures and dynamics o... more In order to improve our understanding and enhancing the knowledge about structures and dynamics of geothermal reservoirs for geothermal exploration and a sustainable use of the resource, we assess geothermal reservoirs with an integrated multi-scale and multi-disciplinary approach. A passive seismic monitoring study started in October 2012 with the deployment of a network of 30 broadband seismic stations and 4 short period seismic stations around a two phase geothermal area in West Java, Indonesia. This geothermal field is situated inside the volcanic zone in the center of West Java. Sediments and volcanic product were deposited less than 50,000 years ago. The presence of a complex tectonic setting may explain co-existence of a large variety of intense surface manifestations like fumaroles, hot-steaming grounds, hot water pools, and active volcanoes (Guntur and Papandayan volcanoes). These co-existent features suggest an intimate coupling between volcanic, tectonic and hydrothermal processes in this area. We describe the set-up of the broadband network and discuss first observations.

Journal of Asian Earth Sciences, 2014

The Tarutung Basin is located at a right step-over in the northern central segment of the dextral... more The Tarutung Basin is located at a right step-over in the northern central segment of the dextral strike-slip Sumatran Fault System (SFS). Details of the fault structure along the Tarutung Basin are derived from the relocations of seismicity as well as from focal mechanism and structural geology. The seismicity distribution derived by a 3D inversion for hypocenter relocation is clustered according to a fault-like seismicity distribution. The seismicity is relocated with a double-difference technique (HYPODD) involving the waveform cross-correlations. We used 46,904 and 3,191 arrival differences obtained from catalogue data and cross-correlation analysis, respectively. Focal mechanisms of events were analyzed by applying a grid search method (HASH code). Although there is no significant shift of the hypocenters (10.8 m in average) and centroids (167 m in average), the application of the double difference relocation sharpens the earthquake distribution. The earthquake lineation reflects the fault system, the extensional duplex fault system, and the negative flower structure within the Tarutung Basin. The focal mechanisms of events at the edge of the basin are dominantly of strike-slip type representing the dextral strike-slip Sumatran Fault 2 System. The almost north-south striking normal fault events along extensional zones beneath the basin correlate with the maximum principal stress direction which is the direction of the Indo-Australian plate motion. The extensional zones form an en-echelon pattern indicated by the presence of strike-slip faults striking NE-SW to NW-SW events. The detailed characteristics of the fault system derived from the seismological study are also corroborated by structural geology at the surface.