Indonesia Conference Directory

Corresponding Author
Wiwin Windupranata

Institutions
1Research Group of Coastal, Ocean and Maritime Engineering, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung
2Center for Earthquake Science and Technology, Research Center for Disaster Mitigation, Institut Teknologi Bandung
3Research Laboratory of Hydrography, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung
4Study Program of Geodesy and Geomatics Engineering, , Faculty of Earth Sciences and Technology, Institut Teknologi Bandung

Abstract
The Southern Coast of West Java Province in the Java Islands is one of prone and exposed area to tsunami hazard. It has about 428 kilometers coastline length, covering 5 administrational regencies (i.e. Sukabumi, Cianjur, Garut, Tasikmalaya, and Pangandaran). It is a strategic area that support many economic activities including tourism, fisheries, electricity power plants, agricultures, markets as well as social factors such as coastal villages, schools and other public facilities. The existence of this strategic area is threatened by the potential for a tsunami disaster mainly from megathrust along the Southern Coast of Java Island. On 2006, a tsunami earthquake of M7.7 occurred off Pangandaran Regency with tsunami height of 5-8 meters and inundated about 500 meters along southern coast of West and Central Java Province. The tsunami caused more than 600 casualties and damage to buildings, public facilities and insfrastructure. Yet, the Indonesia National Earthquake Source and Hazard Map suggest a bigger threat of a plausible M8.7 – M9.2 megathrust earthquake off Java island. This research aims to analyze and map potential areas affected by the tsunami in the South Coast of West Java Province based on numerical modelling carried out with Cornell Multi-grid Coupled Tsunami Model (COMCOT) v1.7 based on the several megathrust earthquake scenarios in southern off West Java. The results of tsunami modelling show that the highest impact is generated in the Sunda Straits & West Java - Central Java Megathrust Scenarios with highest tsunami inundation and the fastest travel time occurred in Cianjur Regency with 26,7 meters height and estimated arrival time of tsunami wave approximately 10 minutes after the mainshock, while the farthest inundation distance is estimated in Sukabumi Regency about 5.8 kilometers from the coast due to existence of river. As an impact of tsunami in socio-economic aspect, Pelabuhan Ratu District in Sukabumi would be the most vulnerable due to high economic activities and number of inhabitants.

Keywords
Tsunami, Megathrust Earthquake, Southern Coast, West Java Province

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/YX9BCLUtavcN

Corresponding Author
Andri Irawan

Institutions
a) Research Center for Deep Sea – Indonesian Institute of Sciences (P2LD-LIPI), Ambon, Maluku, Indonesia
*andri.irawan[at]lipi.go.id
b) Research Center for Oceanography - Indonesian Institute of Sciences (P2O-LIPI), Jakarta, Indonesia

Abstract
Ambon Bay is located on Ambon Island, which most of the area is within the Ambon City, the capital of Maluku Province. Coastal ecosystems such as coral reefs, mangroves, and seagrass beds still exist on this bay. However, as a coastal ecosystem in a crowded city, the potential of degradation for these ecosystems is very large. Over the past five years, many changes have taken place in this bay. In the land section, the construction of housing and large buildings such as shopping centers has occurred. In addition, on the coast, there has been a construction of new docks and several locations have been reclaimed. Therefore, in 2016 there was a re-observation of the seagrass conditions at all transect locations of 2011, to see the changes that have occurred in seagrass beds in Ambon Bay over the past five years. The results will be compared to the satellite imagery of each location. Overall, the condition of seagrass beds in Ambon Bay in 2016 has decreased from the initial observation in 2011. Of the seven research locations, only one location (Halong) has an increase in its conditions, with seagrass canopy cover rise by almost twofold from previous data (24.29% rise to 50.00%). Four locations experienced a decline in conditions, from a slight decrease in Waiheru and Lateri (25.00% down to 20.91% and 47.14% down to 30.00% respectively) to a sharp decrease in Tanjung Tiram and Passo (65.67% down to 39.33% and 48.33% down to 16.25% respectively). The remaining two locations (Tantui and Hative) were in worse condition because they were damaged by the reclamation project. From 2011 and 2016 satellite image comparison, almost all locations show changes in their land use, with more building built near and on the coastal area, except in Halong. This indicates that seagrass condition negatively affected by coastal development.

Keywords
Seagrass, Decline, Coastal development, Pressure, Reclamation

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/tGAPVzEMv9m4

Corresponding Author
Muhammad Rizqy Septyandy

Institutions
Program Study Geophysics
Program Study Geology
Department of Geography
Universitas Indonesia

Abstract
Historically, the Sunda Strait has experienced several tsunamis recorded in the tsunami catalog caused by several geological phenomena. One of the last tsunami events in the Sunda Strait was the tsunami on December 22, 2018. The condition of bathymetry, coastal topography and high rainfall were some of the trigger factors for tsunamis in the Sunda Strait in addition to the eruption of Mount Anak Krakatau. To anticipate a tsunami in the future, a model of the height of tsunami waveforms that arrived at the coast was made. This study focused on producing rapid predictions of tsunami waveforms arriving at the coast using data signals recorded when a tsunami occurs due to landslide sub-marine. The remarkable training speed requires that it can be used to run in real time conditions and can be used as a tsunami early warning system in near-field tsunami events on the west coast of Banten. The proposed method used non-linear relationships by utilizing Sunda Strait bathymetry data, tide gauge signals, and coastal topography along the west coast of Banten, as well as rainfall during the past tsunami. Therefore, it becomes an advantage compared to ordinary inversion analysis that uses linear assumptions. The results of this study indicate that the extreme machine learning method produces more accurate results with a faster time compared to the inversion method in the propagation, tsunami run-up, and inundation zones on the west coast of Banten. In addition, the uncertainty analysis produced by our model proves that this method is robust and reliable, resulting in a model that can be used as a reference for tsunami safety zones by the local government.

Keywords
Tsunami, landslide sub-marine, extreme machine learning, Sunda Strait, inundation zone

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/jL9xGkTud4D3

Corresponding Author
Ismail Abdul Jabbar

Institutions
a) Study Program of Oceanography, Faculty of Earth Sciences and Technology, Bandung Institute of Technology

b) Research Group of Oceanography, Faculty of Earth Sciences and Technology, Bandung Institute of Technology

*) Jl. Ganesha 10, Bandung 40132, Indonesia

Abstract
Extreme wave height analysis has been conducted in Natuna Sea, Indonesia, using 25 years (1991-2015) Significant Wave Heights (SWHs) data from WAVEWATCH 3 (WW3) with spatial resolution of 1/8o. The Natuna Sea is geographically connected to the South China Sea (SCS) and is often crossed by massive storms (cyclones) with wind speeds greater than 30 m/s. These storms may have contributed to the existences of high waves in the SCS, which propagate as swell waves to the Natuna sea and could led to extreme waves in this region. Extreme value analysis has been done by classifying the extreme events of SWHs using Peak-Over Threshold (POT) method with a fixed threshold level at quantile 0.93 and a minimum time separation of 48 hours between two successive extreme events. Furthermore, the Generalized Pareto Distribution (GPD) has been applied to estimate return values of the extreme SWHs for several return periods. The shape and scale parameters of the GPD have been estimated by Maximum Likelihood Estimation (MLE) method. The characteristics of extreme SWHs in the Natuna Sea have been explained by maximum and seasonal distribution plots. Maximum value of extreme SWHs in the SCS can reach 13 m and around 3-5 m in the Natuna Sea. The seasonal distributions of extreme waves indicate that the occurrences of extreme waves in the SCS during Northeasterly Winter Monsoon (NWM) are higher than those during Southwesterly Summer Monsoon (SSM) although the tropical cyclones in the SCS are more likely to happen during SSM. The seasonal mean and maxima of extreme SWHs in the Natuna Sea are also high during the NWM and low during the SSM. To examine effects of swell waves from the SCS and also the future extreme waves in the Natuna Sea, we have analysed the characteristics and calculated the return values of extreme waves in front and behind of Natuna Island, which the former faces directly to the SCS. There are 172 (331) extreme waves happen from 1991-2015 in the front (behind) of Natuna Island and mainly from northeast (southwest). Most of them are around 2-3.5 (0.5-1.5) m with mean period of 7-9 (3-5) s. Moreover, the return values in the front (behind) of the Natuna Island show that there are possibilities of extreme waves with values 4.70, 4.87, and 4.96 (2.08, 2.20, and 2.27) m for return periods of 25, 50, and 75-year, successively.

Keywords
Natuna Sea; Peak-Over Threshold; Generalized Pareto Distribution; extreme waves; return values

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/YNukjBrmUeLq

Corresponding Author
Syafyudin Yusuf

Institutions
a,b Marine Science, Hasanuddin University
c Graduate School of Hasanuddin University
d Bogor Agriculture University

Abstract
Land clearing for mining operations is rampant around Sulawesi. This land opening increases the sedimentation load and eutrophication of the waters so that it disturbs life in the coral reef ecosystem on the coast. The threat of coral death originating from the overflow of sediments that enter the ocean waters is presumed to occur at the coast of the Bone Bay. This study aims to identify indicators of damage to coral reefs around the land mining area of the Northern Bone Bay. Observations of the substrate cover of coral reef ecosystems were carried out in 2015, 2016 and 2017 using a UPT (Underwater Photo Transect) method along 50 meters at a depth of 2 and 6 meters. The ecological impact indicators such as eutrophication and sedimentation used in this study are macro algae cover, dead coral with algae, silt, water clarity, total suspended solid (TSS) and sedimentation rate. The results show that there have been significant changes in live coral cover and other substrates during the study period. Scleractinian coral cover decreased, while dead coral with alga, macro algae, soft corals and sponges cover increased. The cause of coral death is not only by sedimentation and eutrophication, but also due to the occurrence of bleaching in 2016. Very few indications of new destruction due to destructive fishing. High turbidity and TSS concentration observed in this study were caused by sediment supply from the Malili river which is estimated due to mining and land clearing in the surrounding mountains.

Keywords
Coral Reef Degradation, Land Mining, River Overflow, Low seawater quality, Land Mining, Bone Bay Indonesia

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/j89hDLBfvRgH

Corresponding Author
Corry Yanti Manullang

Institutions
1. Center for Deep Sea Research - Indonesian Institute of Sciences

2 & 3 : Research Center for Oceanography, Indonesian Institute of Sciences

Abstract
Since late 2011 mercury has been used to extract the gold requiring in artisanal gold mining in Mt. Botak (Buru Island) and resulting in deposition of mercury into Kayeli Bay. In this project we reported the updated total mercury (THg) concentration in marine sediment and nine spesies of domersal fish from Kayeli Bay. Nine coastal sampling sites were selected in the Kayeli Bay by purposive sampling. The fish are collected from traditional market in Buru Island. The total mercury (THg) concrentrations in marine sediment were found in all sites, ranged from (in mg/kg, dry weight): 0.035 to 4.802. The THg concentrations in sediments from all sites measured were found has exceeded the National Oceanic and Atmospheric Administration (NOAA) value. Among fish, the highest THg concentration of 1.667 mg/kg DW was measured in the muscle species Myripristis kuntee and the lowest THg concentration detected for Lutjanus Lutjanus (0.016mg/kg dw). The distribution of total mercury (THg) concentrations found in marine sediment of Kayeli Bay shows a very closed relationship to the artisanal gold mining activity in Mt Botak..

Keywords
Mercury, artisanal gold mining, marine sediment, fish, Kayeli Bay

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/dgeHJD9YbNwR

Corresponding Author
Munawir Bintang Pratama

Institutions
Department of Ocean Engineering
Institut Teknologi Bandung, Bandung 40132, Indonesia
munawirbintang[at]gmail.com

Abstract
Tidal flood has been an inevitable coastal hazard for some water-front cities in Indonesia, especially in Java Island. Besides Jakarta – the Capital City, Pekalongan City in the North Coast of Central Java is one of the cities suffered. This paper aims to study the effectiveness of coastal dyke in reducing inundation in Pekalongan City using a numerical hydrodynamic model. The model is performed using Delft-3D equipped with spatial data provided by The Indonesian Agency for Geospatial Information. The model is validated against the observed tidal elevation and shows a good agreement. In the validated model, land subsidence and sea level rise are applied. Also, three scenarios of dyke elevation are studied and simulated in 2020, 2030, and 2050. The results presented are the maximum flood depth and the area inundated per scenario.

Keywords
Tidal flood; Coastal hazard; Coastal dyke; Pekalongan

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/Rkat9rfJDHqc

Corresponding Author
Faruq Khadami

Institutions
1 Ocean College, Zhejiang University, Zhoushan, 316021, China;
Correspondence to: Weijie Liu (weijieliu[at]zju.edu.cn)

Abstract
The extents of wave-driven flooding along the coastline fronted by fringing reefs during severe weather depend on the state of the reef. It is believed climate change will result in a net increase in the water depth over the reef flat, a degrading of the surface roughness of coral reefs and changes in extreme incident wave heights. For a better understanding of the impact of climate change on wave-driven flooding hazards over reef-fringed coasts, this study utilized a Boussinesq wave model, FUNWAVE-TVD, to simulate irregular wave transformation and run-up over fringing reefs. Validated with experimental data, the present model shows reasonable prediction of irregular wave evolution and run-up height. Numerical experiments were then implemented based on the anticipated effects of climate change and carried out to investigate the effects of sea level rise, degrading of the reef surface roughness and increase of extreme incident wave height on the irregular wave run-up height over the back-reef beach. Variations of spectral components (i.e., significant sea-swell run-up height, infragravity run-up height and 2% highest run-up height) of irregular wave run-ups were examined and discussed to better understand the underlying physical process.

Keywords
fringing reefs; irregular waves; run-up; climate change; spectral components

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/Tn37xvtNc49k

Corresponding Author
Aswan Aswan

Institutions
Geology Department, Institut Teknologi Bandung (ITB), Jl. Ganesha 10 Bandung, Indonesia (40132); email: aswan_gl[at]gc.itb.ac.id, +62-85314001580

Abstract
Several major tsunami events in Indonesia, such as in Aceh, Pangandaran, Palu and Banten areas, have raised our awareness of the importance of paleotsunami deposits study, especially in relation to the determination of their occurrence time intervals. The Palu and Banten tsunami events have given new perception to the community that tsunami waves can be caused not only by earthquakes but also by landslides (or underwater landslides). One of the problems faced in paleotsunami deposits study is that their sediment show some similarities to those of storm deposits. Another problem is to determine whether the deposits are related to earthquake-induced or landslide-induced tsunamis; hence, it is important to study their characteristics, respectively. Age of tsunami-derived material sedimentation is critical for estimation of tsunami event time intervals in a particular region. Several alternative age determination methods will be discussed in this study, taking into account the estimated age of the tsunami deposits.

Keywords
paleotsunami, deposit, storm, landslides, age

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/nhHk4URgEpvN

Corresponding Author
karina aprilia sujatmiko

Institutions
a) Program Study of Oceanography, Bandung Institute of Technology, Labtek XI, Jl. Ganesha no.10. Bandung, Indonesia.
b) Center for Marine and Coastal Development, Institut Teknologi Bandung, Labtek XI, Jl. Ganesha no.10. Bandung, Indonesia
*karina.sujatmiko[at]oceanography.itb.ac.id

Abstract
West Java coastal areas are endangered by the slow-onset of global sea level rise and the increasing frequency of coastal hazard such as storm surge and coastal flood due to climate change. Located near the subduction zone of Eurasia and Indo-Australia plate, West Java also faced rapid onset disaster such as tsunami especially in the southern coast. Physical vulnerability has implications for socio-economic, infrastructure, and ecosystem conditions of the coastal zones. Therefore, it is substantial to conduct a coastal vulnerability assessment and provide a relevant GIS map. This assessment strengthened by extensive surveys along the coast of West Java and interviews with the local communities. This study discussed potential inundation hazard in the future caused by climate induced hazard in regard with oceanographic parameters such as ENSO, MJO and IOD and local tidal height. Based on recording data and projection it is found that the contribution of La Niña variation as much as 21.7 cm, MJO 24.3 cm, Indian Ocean Dipole mode 16 cm, maximum tidal height is 95.77 cm, global sea level rise projection 0.7 cm/year and increased storm surge up to 150 cm. Using tsunami model for the 100-year return period, the expected tsunami height ranges from 2 to 7 m. A hazard map is developed using a simple analytical model representing occurrence of cumulative hazards of flooding or inundation that could occur in coastal areas according to a scenario of condition. There are selected 10 hazard scenarios based on the combination of hazard elements developed for 2020 - 2050 projection. The extreme climate induced hazard inundation is gained when all parameters, except tsunami, are occurred in conjunction which resulted in extreme height of 334.5 cm in year 2050. While, the combination of climate and tectonic induced hazard inundation resulted in extreme height of 779,6 cm in year 2050. The detailed of inundation potential hazard is then presented into maps by using Geographic Information systems (GIS) and elevation model of Southern coast of West Java.

Keywords
Sea level rise, inundation hazard, tsunami

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/CXyjMeRcTFHA

Corresponding Author
Faruq Khadami

Institutions
1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China.
2. Institute of Marine Geology and Resources, Zhejiang University, Zhoushan 316021, China.
3. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
4. South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
* Corresponding author: Chun-Feng Li, cfli[at]zju.edu.cn

Abstract
In 2016, we carried out a coincidental multi-channel reflection seismic and wide-angle reflection/refraction seismic experiment along a 320-km long profile across the northeastern margin of the South China Sea (SCS). Based on these new data, we studied velocity structure of the transitional continental crust using both ray-tracing based seismic phase modeling and travel-time tomography. The velocity model shows that Mesozoic sediments have velocities of 4.3-5.3 km/s and are about 3-6 km thick in the magnetically quiet Chaoshan Depression and the attenuated transitional continental crust. This confirms that it is this thick layer of weakly magnetized Mesozoic sediments that causes the magnetic quiet zone. This Mesozoic layer pinches out seawards near the continent-ocean boundary. Two apparently isolated high-velocity anomalies are revealed in the lower crust of the continental slope. The first has velocities of 7.0-7.5 km/s and a maximum thickness of 8 km, and the second has velocities of 7.0-7.3 km/s and a maximum thickness of 3 km. We find that the discontinuity of the high-velocity zones is not due to the lack of some seismic phases or lose of a seismometer. We suggest that post-spreading magmatism caused these high-velocity zones. A third high-velocity zone, showing a distinctly large velocity gradient, is revealed near the continent-ocean boundary (COB). This indicates upper mantle upwelling and/or exhumation right at the COB, despite recent unsuccess in directly sampling these deep materials in the SCS.

Keywords
South China Sea, Seismic velocity structures,

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/rWgP7eEjV2w6

Corresponding Author
Sri Redjeki Pudjaprasetya

Institutions
Industrial & Financial Mathematics Research Group, Institut Teknologi Bandung

Abstract
In a disaster event, the impact of the tsunami is measured based on wave height along the coast. During its propagation towards the coast, tsunami wave that develop in the ocean will be amplified due to shoaling. The elevated waves that struck residents in Palu Bay were very severe, far exceeding predictions. Recent research shows that the strike-slip earthquake on 28 September 2018 (Mw 7.5) along the Palu-Koro fault caused several landslides in Palu Bay, which then triggered a significant tsunami wave. Closer investigation, the extreme height of tsunami in Palu Bay was due to geographical factors such as narrowing of the bay, and the presence of a bump in the mouth of the bay, both of which have the same effect, namely wave focusing. Our study here is focused on the effect of bathymetry on wave focusing in bays. The momentum conservative scheme with wet-dry procedure was implemented here to solve the 2-dimensional shallow water model. The scheme is validated via simulation of wave amplification in an (idealized) parabolic bay, to be compared with the existing analytical solution. Next, wave amplification due to a bump on a flat topography will be evaluated. Finally, wave amplification in the mouth of Palu Bay using real topography will be assessed.

Keywords
shallow water equation, tsunami landslide, wave focusing, wave shoaling

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/ukQCNxUMjF7W

Corresponding Author
Heri Andreas

Institutions
Geodesy Research Group, Faculty of Earth Science and Technology, Institute of Technology Bandung
Jalan Ganesha 10 Bandung Indonesia
*heriandreas49[at]gmail.com

Abstract
Many areas of Indonesia are belong to coastal low land area. Geometrically the topography is just only several meter above the sea level and even in some places they are already below the sea level. In the recent few decades the sea is rising (e.g. sea level rise) and the land is sinking (e.g. land subsidence). Both combination of phenomenon has made the coastal low land area prone to sea water inundation or sunny flood (“rob” in Javanese). Clear examples have been found around northern coast of Java and east coast of Sumatra. In certain places in the two islands, the permanent inundation is existed obviously. They are hazard turn to disaster. The losses is huge especially to the material. Millions of Dollar has gone. Creating hazard map of these cases in Indonesia is an urgent need to support mitigation and adaptation against those issues. Nevertheless there are several data and information requirement like Digital Terrain Model (DEM), magnitude of sea level rise and subsidence, etc. which arenot available completely or properly. This is a challenge. This paper will be highlight about those urgent need and the challenge.

Keywords
hazard map, coastal, sea level rise, land subsidence, challenge

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/jyNbDxmnWfQB

Corresponding Author
Corry Yanti Manullang

Institutions
1. undergraduate sudent - Faculty of Fisheries and Marine Science, University of Papua

2. Faculty of Fisheries and Marine Science, University of Papua

3. Center for Deep Sea Research - Indonesian Institutes of Sciences

Abstract
The purpose of this study was to determine the type of microplastic, the amount and abundance and microplastic distribution of large (1-5 mm) and small (<1 mm) based on backshore (BS) and high strandline (HS) zones on Aipiri Beach, Manokwari Regency - West Papua. The study was conducted in March-May 2019 on Aipiri Beach with three replicates sampling times. Microplastic sampling was using quadrant plots. This study was confirmed the pesence of three types (fragmens film and fiber) of microplastic in Aipiri Beach. The highest abundance found was fragmen with 1.18 items / kg.

Keywords
Microplastic, beach sediment, Aipiri Beach, backshore

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/yW4gF3RAkHCU

Corresponding Author
Corry Yanti Manullang

Institutions
1. undergraduate sudent - Faculty of Fisheries and Marine Science, University of Papua

2. Faculty of Fisheries and Marine Science, University of Papua

3. Center for Deep Sea Research - Indonesian Institutes of Sciences

Abstract
Microplastic is one of the most serious problems in the marine environment. In this study we determined the type, amount, abundance and microplastic distribution of large-microplastic (1-5 mm) in the backshore (BS), strandline (SL) and wateredge (WE) zones on Anday Beach - Manokwari Regency, West Papua. Sampling was conducted on March 2019 with three replicates sampling times. The types of microplastic found on Anday Beach are films, fragments, and fibers. About 78% of large-microplastic observed in Anday beach were plastic films. The highest abundance of large-microplastic were found in the BS and WE zones with average of 6.67 items / m².

Keywords
marine debris, microplastic, beach sediment, Anday Beach

Topic
Coastal Degradation and Coastal Hazard

Link: https://ifory.id/abstract/BU8eDrH6R3hM