Dina A. Sarsito

Preliminary deformation model for National Seismic Hazard map of Indonesia

Preliminary deformation model for the Indonesia’s National Seismic Hazard (NSH) map is constructed as the block rotation and strain accumulation function at the elastic half-space. Deformation due to rigid body motion is estimated by rotating six tectonic blocks in Indonesia. The interseismic deformation due to subduction is estimated by assuming coupling on subduction interface while deformation at active fault is calculated by assuming each of the fault‘s segment slips beneath a locking depth or in combination with creeping in a shallower part. This research shows that rigid body motion dominates the deformation pattern with magnitude more than 15 mm/year, except in the narrow area near subduction zones and active faults where significant deformation reach to 25 mm/year.

Deformation analysis of Mentawai islands based on observation GPS data 2013-2016

The islands of Sumatra accommodate the collision of the Indies-Australian plate pressing the Eurasian plate at a speed of 5-6 cm/yr at the boundary between the plates along the west coast of Sumatra (Natawidjaja, D.H., 2007). The oblique collision between the two plates formed a subduction zone in the western part of the island of Sumatra and a number of fault segments on the island of Sumatra. Subduction zones and cesareans segments that are formed actively move so often cause earthquakes in the region. Mentawai islands are located in the westernmost part of Sumatra and belong to the subduction zone of Mentawai Segment Mentawai Islands movement can be identified using GPS observation data. The data used are GPS observation data from 2013 to 2016 coming from Sumatran GPS Array (SuGAr) Network. The data is processed using software GAMIT / GLOBK 10.6. The results of the GPS data processing will be processed to produce velocity velocities and strain values of each GPS observation station used to observe deformation activity on the Mentawai Islands. The results of GPS observation data processing showed vector movement in Mentawai Islands referenced to Sundaland Block leads to the northeast on the northern part of the Mentawai Islands, heading southwest to the southern part of the Mentawai Islands, and heading north to the central part of the Mentawai Islands. The strain obtained from data processing showed that the Mentawai Islands experienced an interseismic phase in the north, a post-seismic phase in the south and a transitional phase in the middle.The islands of Sumatra accommodate the collision of the Indies-Australian plate pressing the Eurasian plate at a speed of 5-6 cm/yr at the boundary between the plates along the west coast of Sumatra (Natawidjaja, D.H., 2007). The oblique collision between the two plates formed a subduction zone in the western part of the island of Sumatra and a number of fault segments on the island of Sumatra. Subduction zones and cesareans segments that are formed actively move so often cause earthquakes in the region. Mentawai islands are located in the westernmost part of Sumatra and belong to the subduction zone of Mentawai Segment Mentawai Islands movement can be identified using GPS observation data. The data used are GPS observation data from 2013 to 2016 coming from Sumatran GPS Array (SuGAr) Network. The data is processed using software GAMIT / GLOBK 10.6. The results of the GPS data processing will be processed to produce velocity velocities and strain values of each GPS observation station used to observe defo...

Correlation between seismic activity and volcano deformation on Sinabung Volcano in February 2017

Sinabung Volcano was once a dormant volcano until a series of eruption occurred on August 27, 2010 [1]. The methodology used in this research is collecting continuous GPS data from observation points around Sinabung Volcano; KBYK, LKWR, MDRG, and SNBG from CVGHM (Center for Volcanology and Geological Hazard Mitigation) in February 2017. Case studies taken in this research are based on eruption column height, there were 2 big eruptions recorded in February 2017, both on February 4 and 8, with eruption column height 5000 m and 3500 m respectively. The data processing is done using RTKLIB Ver.2.4.2. GPS Observation data then processed using RTKLIB Ver.2.4.2 in kinematic positioning mode, where both LKWR and MRDG referenced relatively to KBYK. Time series baseline results of LKWR-MRDG observation points around Sinabung Volcano both in 2D and 3D in February 2017 show different trend, where on February 4, 2D and 3D LKWR-MRDG baselines had some shifting in which baseline causing extension with range around 4 cm away out of the body of volcano right before the eruption started, meanwhile on February 8, 2D and 3D LKWR-MRDG baselines overall show the extension pattern, although baselines had back and forth patterns. Correlation between seismic z-component and time series displacement result on the up-down component in LKWR on both February 4 and 8 show a positive correlation, where similar patterns seen in 5 minutes before eruption, during eruption event, and 5 minutes after eruption.Sinabung Volcano was once a dormant volcano until a series of eruption occurred on August 27, 2010 [1]. The methodology used in this research is collecting continuous GPS data from observation points around Sinabung Volcano; KBYK, LKWR, MDRG, and SNBG from CVGHM (Center for Volcanology and Geological Hazard Mitigation) in February 2017. Case studies taken in this research are based on eruption column height, there were 2 big eruptions recorded in February 2017, both on February 4 and 8, with eruption column height 5000 m and 3500 m respectively. The data processing is done using RTKLIB Ver.2.4.2. GPS Observation data then processed using RTKLIB Ver.2.4.2 in kinematic positioning mode, where both LKWR and MRDG referenced relatively to KBYK. Time series baseline results of LKWR-MRDG observation points around Sinabung Volcano both in 2D and 3D in February 2017 show different trend, where on February 4, 2D and 3D LKWR-MRDG baselines had some shifting in which baseline causing extension with range around 4 cm ...

Implementation of M6.5 Pidie Jaya earthquake’s deformation model for Indonesian geospatial reference system 2013

On Tuesday 06 December 2016, the magnitude 6.5 earthquake occurred near Pidie Jaya district of Aceh province, Indonesia. Indonesian National Board for Disaster Management reported, this earthquake causing 106 casualties, 700 injuries, 16238 house damages, and 85161 evacuate. The horizontal deformation due to this earthquake has been recorded by continuous GPS (cGPS) network belong to Geospatial Information Agency and National Land Agency. The nearest cGPS to the epicenter is around 32 km that has horizontal deformation about 2.5 cm to west and 0.5 cm to north direction. Using simple modeling, we estimate coseismic deformation due to this earthquake associated with the Indonesian Geospatial Reference System 2013 (IGRS2013) and the implementation.On Tuesday 06 December 2016, the magnitude 6.5 earthquake occurred near Pidie Jaya district of Aceh province, Indonesia. Indonesian National Board for Disaster Management reported, this earthquake causing 106 casualties, 700 injuries, 16238 house damages, and 85161 evacuate. The horizontal deformation due to this earthquake has been recorded by continuous GPS (cGPS) network belong to Geospatial Information Agency and National Land Agency. The nearest cGPS to the epicenter is around 32 km that has horizontal deformation about 2.5 cm to west and 0.5 cm to north direction. Using simple modeling, we estimate coseismic deformation due to this earthquake associated with the Indonesian Geospatial Reference System 2013 (IGRS2013) and the implementation.

Investigating the tectonic subsidence on Java Island using GNSS GPS campaign and continuous

Many places around Java island are experiencing land subsidence with the rates vary from few centimeter to order of tens centimeter per year. Question arises on what would be the causes of the subsidence in the area. The tectonic is one of the suspected causes along with anthropogenic causes (e.g. ground water overexploitation). The question is very important for proper and effective mitigation or adaptation. As we can see the impact from subsidence like damaging on infrastructures, wider area expansion of flood, etc. indeed they are formed a quite serious disaster now. If the tectonic play significant role, in this case the adaptation is more effective than mitigation, etc. GNSS GPS technology is a passive, all-weather satellite-based navigation and positioning system, which is designed to provide precise three dimensional positions and velocity, as well as time information on a continuous worldwide basis. In the context of subsidence as we highlight above, GPS could provide very accurate level (millimeter level) to determine the subsidence signal if existed. This paper will highligt the investigation of tectonic subsidence over Java island by using data measurements from GNSS campaign and continue. Our preliminary result shows no tectonic subsidence over Java island.Many places around Java island are experiencing land subsidence with the rates vary from few centimeter to order of tens centimeter per year. Question arises on what would be the causes of the subsidence in the area. The tectonic is one of the suspected causes along with anthropogenic causes (e.g. ground water overexploitation). The question is very important for proper and effective mitigation or adaptation. As we can see the impact from subsidence like damaging on infrastructures, wider area expansion of flood, etc. indeed they are formed a quite serious disaster now. If the tectonic play significant role, in this case the adaptation is more effective than mitigation, etc. GNSS GPS technology is a passive, all-weather satellite-based navigation and positioning system, which is designed to provide precise three dimensional positions and velocity, as well as time information on a continuous worldwide basis. In the context of subsidence as we highlight above, GPS could provide very accurate level (millimet...

Long term variation of sea level anomaly (September 1992-January 2017) in the Indonesian sea from multi-mission satellite altimetry data

Sea level anomaly (SLA) is one of the oceanic parameters that play a crucial role in the ocean dynamics. In the Indonesian region, spatio-temporal characteristic of SLA is significantly affected by local topographic features of the region. In this research, we investigate long-term variation of SLA over the region based on Topex/Poseidon, Jason-1 and Jason-2 data, during the period of Sept 1992 to January 2017. After removing some geophysical effects, time series of SLA values at each point of the collinear tracks are analyzed. The result show the long term MSSH in Indonesia area have increase from western part of Indonesia to eastern part with range -40 m to 80 m. The long term SST in Indonesia have almost same trend with the deviation from geoid undulation full degree with short wavelength type, and this phenomena represent the local effect such as shallow bathymetry and close sea. And for long term SLA, Indonesia shows positive value that the anomaly increasing with variable from western part to eastern part of Indonesia from 2.5 mm/year until 7 mm/yr.

Early pictures of global climate change impact to the coastal area (North West of Demak Central Java Indonesia)

In the last several decades we have been realized for the Global Climate Change situation. Some indicators are worldwide increasing temperature, decreasing volume of ice in Antarctica, and the sea level rise. Relating to the decreased of ice volume and the sea level rise, this situation has been predicted to endanger the living at the coastal area in the future. Prediction models have shown some coastal cities area would suffer flood by tidal inundation and even permanent flooding. Coincidently, today in the North West of Demak District Central Java Indonesia we literally can see the early picture of Global Climate Change impact to the coastal areas as mention. The occurrence of tidal inundation in this area was recognized at least in the early 2000 and even earlier, and in the recent years the tidal inundation comes not only at a high tide but even at the regular tide, and in fact some of this area are obviously sinking to the sea through times. This early picture is truly showing a disaster. Adaptation ...

Strain analyis in Banda Sea using grid strain based on GPS observation

Eastern Indonesia has very high deformation due to tectonic activity in triple junction area. Convergencing between plate in Eastern Indonesia trigger some microblocks. Tectonic block as one of deformation phenomenom due to the interaction of between plates can be understood by using strain analysis. Strain analysis shows the change of position, shape and dimension from an object. This research use 80 GPS from previous study by Koulali et al, (2015) and 7 continuous GPS in Bird’s Head to calculate strain rates in order to find relation between tectonic activity and strain rates in Banda Sea, and to identify block boundary. The GPS data are calculated using GAMIT/GLOBK software to obtain time series in each station. Strain rates are calculated using softwae package named grid strain which calculate strain based on interpolation using discretized geodetic measurement resulting strain rates in grid system. The data distribution and algorithm in grid strain influence the result of strain rates from grid strai...

Deformation analysis of Aceh April 11th 2012 earthquake using GPS observation data

This research tries to estimate the co-seismic deformation of intraplate earthquake occurred off northern Sumatra coast which is about 100-200 km southwest of Sumatrasubduction zone. The earthquake mechanism was strike-slip with magnitude 8.6 and triggering aftershock with magnitude 8.2 two hours later. We estimated the co-seismic deformation by using the GPS (Global Positioning System) continuous data along western Sumatra coast. The GPS observation derived from Sumatran GPS Array (SuGAr) and Geospatial Information Agency (BIG). For data processing we used GPS Analyze at Massachusetts Institute of Technology (GAMIT) software and Global Kalman Filter (GLOBK) to estimate the co-seismic deformation. From the GPS daily solution, the result shows that the earthquake caused displacement for the GPS stations in Sumatra. GPS stations in northern Sumatra showed the displacement to the northeast with the average displacement was 15 cm. The biggest displacement was found at station BSIM which is located at Simeuleu...