NUMERICAL SIMULATION OF TSUNAMI FORSCENARIO EARTHQUAKES ALONG THE
MYANMAR (BURMA) SUBDUCTION ZONEOO THAN
MEE09181

Supervisor:

Bunichiro SHIBAZAKI 
Yushiro FUJII 

ABSTRACT
We performed tsunami simulations for the tsunami hazard assessment along the coastline of
Myanmar. We considered four scenario earthquakes along the Burma (Myanmar) subduction zone,
eastern margin of the Indian Plate, with the same depth range of the fault and different locations. Dip
angles are determined based on the high-resolution hypocenter distributions along the Burma(Myanmar) subduction zone. We used 8 tide gauge stations and 42 assumed stations along the
Bangladesh and Myanmar coasts as output points. To examine the maximum heights and travel timesof tsunami at all output points, we performed numerical simulations by using TUNAMI-N2 with
GEBCO 1 arc-minute grid size bathymetry data.
The case A source is located on the subduction interface on land and near the Bangladesh
coast and the maximum tsunami heights generated by this source are less than 1.0 m in the
Bangladesh coast and are less than 0.1 m in the Myanmar coast. The case B source is also mainly
located on the subduction interface on land. The maximum tsunami heights of the case B are less than
1.0 m in the Bangladesh coast and are less than 0.5 m in the Myanmar coast. The case C source islocated on subduction interface beneath the sea, located in the Rakhine coast, western part of
Myanmar. For this case, the maximum tsunami height of 3.261 m is calculated at TG23 station,
located in the Rakhine coast, and the height is less than 2.0 m along the Ayeyarwady delta region.
The case D source is located in the Andaman trench near the Ayeyarwady delta region. The
maximum tsunami heights of the case D are less than 1.0 m along the Ayeyarwady delta region. The
case D source cannot generate a great tsunami because the fault system is almost strike-slip fault.
Keywords: Tsunami, Numerical simulation, Assessment.

1. INTRODUCTION
Myanmar is one of earthquake prone countries in the world because of its location in active
Alpide-Himalayan seismic belt. According to historical record of tsunami, the Arakan earthquake
occurred on 2 April, 1762, 250 years ago which had generated tsunami and the wave arrived at the
Rakhine coast, western part of Myanmar. Myanmar experienced the tsunami effect caused by theSumatra earthquake. After the 2004 Sumatra earthquake, some researchers predicated the possibilityof the occurrence of a tsunamigenic earthquake from the northern part of the Andaman trench to the
Bay of Bengal (Cummins, 2007). Therefore, Myanmar coastline regions are unsafe for the predictedtsunamigenic earthquake. Although historical record is poor in this region, we study about somescenario earthquakes through numerical simulation to mitigate the tsunami hazard disaster to local
people along the coast and around the Bay of Bengal and Andaman Sea.


Department of Meteorology and Hydrology (DMH) of Myanmar.
International Institute of Seismology and Earthquake Engineering/Building Research Institute, Tsukuba,
Japan.
1

2. DATA AND METHOD OF COMPUTATION
2.1 Bathymetry Data
Accurate bathymetric data is necessary for simulation of tsunami propagation. We use the General
Bathymetric Chart of the Oceans (GEBCO) bathymetry data in this study, which is available from thewebsite (http://ngdc.noaa.gov/mgg/gebco). The interval of grid space used in this study is 1 arc-minute(1844.20 m and 1774.49 m in longitude and latitude direction, respectively).
2.2 Tsunami Simulation
We obtained the tsunami maximum heights and tsunami travel times at the coastal output points fromthe numerical results the tsunami propagation for all cases. For tsunami calculation based on the
non-liner shallow water equations with bottom friction terms, we used TUNAMI-N2 code developedby the Disaster Control Research Center (DCRC) of the Tohoku University, Japan (Imamura et al.,2006; Koshimura, 2010).
2.3 Source Parameters of Scenario Earthquakes
In this study, we considered the four sources ofscenario earthquakes for the tsunami simulation along
the Burma (Myanmar) subduction zone (Figure 1).
Firstly, we measured the starting and ending points ofthe fault (fault length) and then the strike angle iscalculated from the trench alignment. Dip angle wasassumed based on the cross-section of relocatedearthquakes along the Burma Plate from the study by
Hurukawa et al. (2010). The rake angle wasdetermined using the plate motion direction of the
Indian Plate with respect to the Burma Plate. The
bottom depth of fault was assumed to be 30 km for allcases. The fault width was calculated by the equation;W  30km

Figure 1. Four scenario earthquakes along
the Burma (Myanmar) subduction zone.

sin , where  is dip angle for eachsource. The magnitude and slip amount were
calculated by using the Papazachos et al. (2004)
scaling law for all cases. Table 1 shows theparameters of fault setting for all cases and the initialconditions of the seafloor deformation are shown in
Figure 2.

Table 1. Source parameters of four scenario earthquakes along the Burma (Myanmar) subduction zone
Top Bottom
Slip
Length Width depth depth Dip Strike Rake
Longitude
Scenarios M
amount Latitude(km)(km) of fault of fault (°) (°)
(°)
°E
°
N
(m)
(km) (km)Case A 8.5 210.054 144.3
030
12 339 124
4.51 21.8823 91.875
Case B 8.5 221.338 144.3
030
12 332 118
4.68 20.0588 92.8125
Case C 8.9 358.794 172.811 030
10 341 127
7.67
17.00
93.9375
Case D 8.3 495.048 42.427
0
30
45
26
172
3.43
13.00
91.875
M = Magnitude of the scenario earthquake

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Case A

Case B

Case C

Case D

Figure 2. Seafloor deformations as the initial condition of case A, B, C and D.
Yellow rectangles are the fault areas. Red and blue lines represent the upliftand subsidence, respectively, with the contour interval of 0.1 m.
2.4 Tide Gauge Stations
We selected 50 tide gauge
stations along the coast of
Bangladesh and Myanmar as
output points (Figure 3).
These are selected to computetsunami waveforms at target
points, and to secure accuracyof tsunami wave height andarrival time for each point. 42
stations are assumed to be atcoastlines in the Bay of
Bengal and the Andaman Sea
and two stations are operated
by Myanmar; at Sittwe and at
Mawlamyine(Moulmein)
which are part of the Global
Sea Level Observing System(GLOSS) of Intergovernmental
Oceanographic
Commission (IOC). 6 stationsareoperatedbytheBangladesh Inland Water
Transport Authority (BIWTA).
These were taken from Sarker(2007). Some places of output
points are highly dense inhigh population and tourist
areas along the coastlines.
Figure 3. Existing and assumed tide gauge stations along the
Bangladesh and Myanmar coasts. The yellow triangles indicate
BIWTA’s tide gauges along the Bangladesh coast. Red triangles
are operated stations by Myanmar and blue triangles are assumed
stations along the Myanmar coast.

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3. RESULTS AND DISCUSSION
3.1 Tsunami Heights
Tsunami heights are obtained from tsunami simulation at all tide gauge stations. We read the valuesof the tsunami heights at each tide gauge station every second until 720 min (12 hrs). The details of
the maximum tsunami height at each output point of all cases are shown in Figure 4.
In the case A, the maximum tsunami height reached 0.614 m at Sandwip (TG04) and thesecond maximum tsunami height arrived 0.447 m at Char Changa (TG03), which are located atlatitude of 22.48°N and longitude of 91.4°E, and latitude of 21.13°N and longitude of 91.12°E in the
Bangladesh coast. For this case, the maximum tsunami height is less than 0.7 m in the Bangladesh
coast and 0.1 m, the smallest tsunami height in the Myanmar coast.
In the case B, the maximum tsunami height reached 0.922 m at Cox’s Bazar (TG05), which
is located at the coordinate of 21.42°N and 91.97°E in the Bangladesh coast and the second maximum
tsunami height reached 0.44 m at TG11 which is located at the coordinate of 20.0209°N and
93.3643°E in the coastline of Myanmar. Shahpuri Island (TG06), TG07, TG08, TG09 and Sittwe(TG10) have no tsunami wave according to the computation because these stations are at uplifted
region side caused by deformation of the fault. However, we obtained the tsunami wave height near
the stations.
In the case C, we obtained the maximum tsunami height of 3.261 m at TG23 which islocated at latitude of 17.9759°N and longitude of 94.4404°E and the second maximum height of
2.761 m at TG21 which is located at latitude of 18.4557°N and longitude of 94.3117°E. In this case,the highest tsunami wave occurred along the Rakhine coast, western part of Myanmar. This case is
the tsunami generated by the largest source in this study. In this case, TG14, TG15, TG19, TG24,
TG26 and TG27 have also no tsunami wave such as the case B. The maximum tsunami height
between 2 m and 3.5 m at 7 tide gauge stations and between 1 m and 2 m at 11 tide gauge stations
along the Rakhine coast, western part of Myanmar and Ayeyarwady delta region.
In the case D, we obtained the maximum tsunami height of 0.853 m at TG28 and thesecond maximum height of 0.305 m at TG27 along the Ayeyarwady delta region, which are located atlatitude of 16.8505°N and longitude of 94.389°E, and latitude of 16.9662°N and longitude of
94.4398°E respectively. The maximum tsunami height is less than 1.0 m along the Ayeyarwady deltaregion.
According to simulation, the maximum heights are less than 1 m in cases A, B and D.
Therefore, we can say that characteristics of these events will be small in terms of damages on the
coastlines of Bangladesh and Myanmar.

Figure 4. Maximum tsunami height at each output point of all sources. Blue
curve, red, green and purple curves represent the maximum tsunami heightof case A, B, C and D, respectively.

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3.2 Tsunami Travel Times
Tsunami travel times were obtained from the results of tsunami waveforms for four scenario
earthquakes at 50 tide gauge stations along the Bangladesh and Myanmar coasts as shown in Figure 5.
Tsunami arrival times for case A, whose Magnitude is 8.5, calculated at all output points, indicate thatthe first waves arrived at Char Changa (TG03), Sandwip (TG04), Cox’s Baza (TG05) and Shahupuri
Island (TG06) in the Bangladesh coast and TG07 and TG08 along the Myanmar coast, respectively at
0 min. These stations are very close to the source. We obtained the result of the tsunami waves at
TG09 to TG33 within 100 min except for TG20 (103.61 min) and in between 176 min and 186 min at
the TG34 to TG36 stations located along Myanmar coast. The Andaman Sea, located between
Ayeyarwady delta region and Taninthari coast (see Figure 3), is an area of shallow bathymetry. This
explains the late tsunami arrivals (over 250 min) at the TG37 to TG50 stations located in this area as aprocess of the slow propagation of tsunami waves.

Figure 5. Tsunami arrival times estimated from waveforms at each output point of all sources.
Tsunami arrival times for the case B, whose magnitude is 8.5, are also calculated at all tidegauge stations. At tide gauge stations of Sandwip (TG04) to TG16, first waves arrive at 0 min.
Mawlamyine (TG43) station exists inside of a River. Therefore, tsunami waves reach later than otherstations and tsunami travel times are calculated at 637.08 min (10.62 hrs) of case A, 588.09 min (9.80hrs) of case B, 482.05 min (8.03 hrs) of case C and 391.01 min (6.52 hrs) of case D after theearthquakes origin time.
The case C has the magnitude of 8.9 and that is the largest one in this study. We also
calculated tsunami travel times from waveforms at each tide gauge station. Tsunami waves arrived at
0 min at the tide gauge stations of Sittwe (TG10) to TG29 because those are very close to the source.
For the remaining tide gauge stations in Bangladesh coast it took longer than 100 min at Hiron Point(TG01) to Cox’s Bazar (TG05) and Shahpuri Island (TG06), at which the wave reaches at 62.26 min.
As for the tide gauge stations in Myanmar coast, the first wave was calculated at 10 min to less than
60 min at TG07 to TG09 and TG30 to TG34, located in Rakhine coast and Ayeyarwady delta region.
As for the remaining tide gauge stations of TG35 to TG50, located in Ayeyarwady delta region and
Taninthari coast, tsunami waves reach there at more than 100 min.
The case D has the magnitude of 8.3 and we also computed tsunami arrival times fromwaveforms at each tide gauge station. Tsunami waves arrived between at 151 min and 354 min at the5coastal output points of Bangladesh. In Myanmar coast, the waves were calculated at 0 min at TG29
to TG32 that are very close to the source, and at less than 10 min at TG17, TG23, TG24, TG26 andTG27, between 10 min and 20 min at TG21, TG22, TG25 and TG33, and less than 35 min at TG12,
TG15 and TG34, and more than 50 min at Sittwe (TG10), TG11, TG13, TG14, TG18, TG19 andTG20. The tsunami arrival times are very late (over 100 min) to reach the TG35 to TG50 stations
located in the shallow water areas.

4. CONCLUSIONSIn order to understand the hazard assessment of tsunami, and we have worked with four scenario
earthquakes along the Arakan and Andaman trenches, Burma (Myanmar) subduction zone,
considering different locations of sources. The maximum tsunami heights and arrival times are derived
from the tsunami simulation at each case.
The case A source is located on the subduction interface on land and near the Bangladesh
coast. The case B source is also mainly located on the subduction interface on land. The case C source
is located on subduction interface beneath the sea, located in the Rakhine coast, western part of
Myanmar. The case D source is located in the Andaman trench near the Ayeyarwady delta region. The
case D source is almost strike-slip fault.
According to the tsunami simulation, the maximum tsunami heights of case A, case B andcase D along the Bangladesh and Myanmar coasts are less than 1 m. Especially, the maximum tsunami
heights of case A are nearly 0.7 m in the Bangladesh coast and 0.1 m in the Myanmar coast. Therefore,
we can conclude the sources of case A, case B and case D cannot generate a great tsunami.
For case C, the obtained maximum tsunami height is nearly 3.5 m. It is the highest one inthis study (see Figure 4). The maximum waves were predicated in the Rakhine coast and the tsunami
arrived at tide gauge stations at the same time of the earthquake occurrence. Therefore, there is notenough time to disseminate tsunami warning, especially for the residents of Rakhine coast, westernpart of Myanmar. The maximum tsunami height is 0.3 m in the Taninthari coast and 1.7 m in the
Ayeyarwady delta region for the case C.
Rakhine coast is much closer to all the sources. Therefore tsunami arrival times for all thecases are earlier at Rakhine coast than at Ayeyarwady delta region and Taninthari coast. For some tidegauge stations along the Rakhine coast, arrival times of tsunami are 0 min or less than 100 min.
Ayeyarwady delta region is closer than Taninthari coast to the source of the case D. Therefore, in thiscase, the waves reach to Ayeyarwady delta region earlier than to Taninthari coast.

AKNOWLEDGEMENT
I would like to express my sincere and hearty gratitude to Dr. Nobuo Hurukawa for his supporting andsuggestions during my individual study.

REFERENCES
Cummins, Phil. R., 2007, Nature 449, 75-78 doi: 10.1038/nature06088.
Hurukawa, N., Pa Pa Tun, and Shibazaki, B., 2010, IISEE/BRI, Tsukuba, Japan.
Imamura, F., Yalciner, A. C., and Ozyurt, G., April 2006 Revision, DCRC, University, Japan.
Koshimura, S., IISEE Lecture Note 2010, IISEE/BRI.
Papazachos, B. C., Scordilis, E. M., Panagiotopoulos, D. G., Papazachos, C. B., and Karakaisis, G. F.,
2004, Bulletin of the Geological Society of Greece, Vol. 36, 1382-1489.
Sarker, N. C. D., 2007, IISEE/BRI and GRIPS, Japan.

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