Download Tsunami Wave Impacts on Coastal Morphological Changes and

Numerical simulations for Investigation of the
Coastline Erosion due to the 2004 Indian Ocean
Tsunami
Syamsidik, Musa Al’ala, Mirza Fahmi, and Tursina
Tsunami Computation and Visualization Laboratory
Tsunami and Disaster Mitigation Research Center
(TDMRC), Syiah Kuala University, Indonesia
Introduction
•
After more than one decade of the 2004 Indian Ocean tsunami, the tsunami affected coastal areas
have another state of of its natural balance, shaping a new coastal line. Some of the areas bounced
back to re-create a coastal line almost similar to the condition before the 2004 tsunami.
•
However, some of the affected coast could not being recovered until the present due to some
factors.
•
The tsunami affected regions in Aceh of Indonesia are mostly located around the South-Western
Coast of the Sumatra Island. This area was told to have a number of tsunamis since 1,000 years ago
(Monecke et al., 2008). This reflects the vulnerability of the region towards the tsunami.
Considering the state of the area towards the tsunami, it would be necessary to understand the
process of the coastal recovery around this area that can be used for further coastal zone
management.
•
The objective of this paper is to investigate the impacts of the tsunami waves on the area by means
of numerical simulations and to monitor the land use changes around the coastal area that were
driven by the coastal morphological recovery process.
•
Unlike other areas around the Indian Ocean, less attention has been put to observe the detail
coastal process contributing to the impacts of the tsunami waves and the coastal recovery process.
Other studies could be found around Tohoku region of Japan after the 2011 Great East Japan
Earthwquake and Tsunami/GEJET (Tanaka et al., 2014).
Study Area:
Teluk Ulee Lheue
Before the 2004 tsunami
After the tsunami
Data Preparation
1. Bathymetri Data
– GEBCO- Layer 1-3
– DISHIDROS TNI AL Layer
4-5
– Public Works Dept 2006
layer 5
2. Topography Data
– Acepmap.com
– Public Works Indonesia
Simulation Domain:
Ulee Lheue Bay
Simulations
• Tsunami Wave Propagation Simulations:
– Initial Waves used Romano (2009) based on mulfi
fault scenarios for the 2004 Tsunami;
– Layer 1-4 were simulated using Cornell Multi-Grid
Coupled Tsunami Model (COMCOT);
– Layer 5 (the innermost layer) was simulated using
DELFT3-D Flow, where the boundary condition
was adopted from results of tsunami waves
propagation produced by COMCOT.
Ocean (0.013)
Beach (0.020)
Ponds (0.017)
Paddy Field (0.022)
Forest (0.035)
Housing (0.040)
Manning
Coefficients
Sediment
Characteristics
Mountain
Coastline before tsunami
Very Fine Sand
Fine Sand
Medium Fine Sand
Coral
Results Validation
Validation of tsunami wave heights from
Jason1
Initial Waves
Tsunami wave heights around the near
shore area
Tsunami Waves Propagation around
the Study Site
Initial Waves
Proses penjalaran tsunami dengan model COMCOT
Layer 1
Layer 4
Tsunami Inundation Area
Proses penjalaran tsunami dengan model Delft3D
Water Depth
Cumulative erosion and sedimentation
Coastal Line Changes
Sea
Land
Coastline before tsunami
Simulated Coastline
Coastline after tsunami
Time after tsunami (sec)
Time after tsunami (Local Time)
Coastal Profile Changes
Cross 1
Cross 1
Distance at Cross Shore
Cross 2
Cross 2
Distance at Cross Shore
Perubahan profil pantai
Perubahan profil pantai pada Cross 3
Cross 3
Perubahan profil pantai pada Cross 4
Cross 4
Erosion and Deposit of sediment due to tsuanmi waves
Hillside
Initial coastline
Recovery of the Coastal Area after 12Year of the tsunami
Year 2003
Year 2005
Tahun 2010
Year 2011
Year 2015
Mangrove Area
Housing Area
Cummulative Area of Housing Complex in the Study Area
300000
250000
Shifting closer to the coastline
200000
2015
Area (m²)
2014
150000
2013
2011
2010
100000
2009
2005
50000
2003
0
100
-50000
200
300
400
500
600
700
800
900
1000 1100 1200 1300 1400 1500 1600 1700 1800
Distance from shore line (m)
Conclusions
• Numerical simulations and spatial analysis were performed in this
research to observe the impacts of the 2004 Indian Ocean tsunami and
also the coastal area recovery process during one decade after the
tsunami.
• The tsunami inundation area based on the numerical simulations has been
confirmed to actual data of the tsunami inundation limit. Although the
erosion process due to the tsunami waves has been fairly agreeable to the
actual data, the simulation has successfully proven the severe erosion
process at some points in the study area.
• The coastal recovery process around this study area shows a return of new
coastal line after one-decade of the 2004 tsunami. Furthermore, the
coastal settlement has been seen to take place at the same location where
it was before the tsunami.
• Land use types in the coastal area seem to follow the land use pattern
before the tsunami. Despite this, some paddy field areas could not be
recovered due to high salinity intrusion around the area.
Thank you