活断層・古地震研究報告，No. 6, p. 171-188, 2006

Paleoseismological field survey along the western coast of Myanmar
Than Tin Aung1, Yukinobu Okamura2, Kenji Satake3, Win Swe4, Tint Lwin Swe5,
Hla Saw6 and Soe Thura Tun7
1, 2, 3

Active Fault Research Center, GSJ/AIST, aung-than@aist.go.jp
4
Myanmar Geoscience Society
5
Yangon Technological University
6
Department of Meteorology and Hydrology, Myanmar
7
Myanmar Earthquake Committee

Abstract: Our field survey was aimed to investigate the geological and geomorphological evidences ofpast earthquakes and tsunamis, particularly the AD 1750± and 1762 events, occurred along the northern
extension of the 2004 Sumatra-Andaman earthquake source. Survey of tsunami deposit, marine terrace,
coral reef as well as the 2004 tsunami heights, were made at 29 points around two cities, Sittway andThandwe, on the western coast of Myanmar. No clear evidences of tsunami deposit and uplifted coral
reef due to past earthquakes were recognized. However, marine terraces at Myengun and Tandin coasts
near Sittway City indicate occurrence of three uplift events during the past 3000 years. Distribution andelevation, higher oceanward and lower continentward, of these terraces could also be considered ascontinentward crustal tilting due to subduction tectonics along the Sunda-Andaman trench offshore thewestern coast of Myanmar.
Keywords: Paleoseismological survey, Tsunami deposit, Marine terrace, Coral, Western coast of
Myanmar

1. Introductionin the central Myanmar were also listed as the actionplans. Under these circumstances, scientists from
Geological Survey of Japan/AIST planned to conduct the
paleoseismology survey of the western coast of Myanmar
with collaboration of Myanmar Earthquake Committee(MEC) and Myanmar Department of Meteorology andHydrology (DMH).

The giant Sumatra-Andaman earthquake andensuring tsunami on 2004 December 26 is one of therecent examples exhibiting the activity of subduction
along the Sunda Trench. Occurrences of such large
earthquakes and tsunamis, Mw > 7.0 since the 1797 along
the Sunda-Andaman Trench off west coast of Java,
Sumatra and Andaman islands over the period of about
three hundreds years have now been verified based on the
paleoseismological and historical records (Chhibber 1934,
Heck 1947, Berninghausen 1966, Ortiz and Bilham 2003,
Sieh et al. 2004). However, the paleoseismicity of thenorthern extension of Sunda-Andaman Trench along thewestern coast of Myanmar has been poorly known.
In December 2005, “Memorial conference on the2004 Giant Earthquake and Tsunami in the Indian Ocean”
was held in Tokyo with a support from the Japanese
Ministry of Education, Sports, Culture, Science andTechnology. Scientists from various researchorganizations, from Japan and the affected countries
around northeastern Indian Ocean, and also from otherexperienced international societies, were gathered. The
conference outlined several action plans that should benecessarily worked out for prevention of future tsunami
and earthquake disaster around the Indian Ocean, mainly
focusing on the 2004 event. Paleoseismology of thewestern coast of Myanmar and the Sagaing strike-slip fault

2. Tectonics and Seismicity of Sunda Trench and Its
Northern Extension, the Western Coast of Myanmar
The Sunda Trench is tectonically and seismicallyquite active subduction zone along which the Indian plate
has been subducting beneath the Burma microplate.
Tectonic configurations of Sunda trench and its northern
extension offshore western coast of Myanmar can begenerally explained by the movement of Indian plate withrespect to the Eurasia plate. The northeastward motion ofIndian plate with relative velocity ~ 3.5 cm/yr decomposes
into ~ 2.0 cm/yr of oblique subduction along the SundaAndaman trench offshore the western coast of Myanmar(northern portion of survey area by Nielsen et al. 2004), ~1.8 cm/yr right-lateral motion along the Sagaing Fault,
inland part of Myanmar (Vigny et al. 2003, Socquet et al.
2006) and eastward motion beneath the Sumatra Island(Fig. 1). However, kinematics of two minor plates between
the two major plates, Burma microplate and Sunda plate,
are still controversial.

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Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

The Burma microplate, the name firstly proposed
by Fitch (1972) as partitioned zone bounded by the SundaAndaman subduction zone in the west and right-lateral
strike-slip fault in the Andaman Sea which extends to theonshore central Myanmar as the Sagain Fault in the east,is driven by the oblique convergence of the Indian plate
relative to the Eurasia and Sunda plates. According todigitized geodetic data, the Burma microplate has an archshaped with north-south elongation of ~ 1500 km andmaximum width in east-west of ~ 400 km (Bird 2003).
The formation of this microplate is considered due to thecollision of Indian plate with Sunda plate since 32Ma, andits present motion and deformation is chiefly governed by
the back-arc opening at Andaman ridge since 4 Ma and the
motion of the two plates, India and Sunda plates (Curray2005).
Kinematics of these plate motions makes thecrustal deformation and intense seismicity in and aroundthe Sunda-Andaman Trench. Past seismicity (1897-1997)
from both inland and western coast of Myanmar are quite
shallow (< 70 km) and show active nature of plateboundaries around the Burma microplate. GPS data also
support high seismicity, and fault models based on GPS
measurement give forecast of possibility to produce amagnitude 8.5 earthquake on every century (Socquet et al.
2006).

three terraces differing each other in level by 6 or 8 feet,showing that the island underwent elevation three times. It
is believed that the main movements took place about the
middle of the seventeenth century, while the last phaseoccurred about the year 1750, when it was accompanied
by a very violent earthquake.
But he seems to be somewhat suspicious about
the ca 1750 earthquake, as he further continues as follows.
These changes in the elevation of the Arakan coast, stated
to extend over more than 100 miles, were attributed by
Captain Halsted to the severe earthquake of 1762. Men
were living at the time of Captain Halsted’s visit in 1841
who had fished over the then dry land. But the evidence
was considered by Mallet to be extremely vague, and theattribution of the changes to the earthquake is entirely
vague, and the attribution of the changes to the earthquake
is entirely a matter of assumption.
In the catalog of tsunamis in the Indian Ocean,Berninghausen (1966) listed both ca 1750 and 1762
events, while he noted the possibility of one event.
1750± Burma coast, Chedula Island, Several small nondamaging waves; fish were stranded. These waves may
have been caused by and eruption of a mud volcanoe ormore likely by the earthquake of April 12, 1762, (Mallet,
1878), see below.
1762 April 12, Earthquake felt most severely along thenorth western coast of the Bay of Bengal. Waves as highas six feet were reported from the distributaries of theGanges Delta.
The 1881 earthquake with Mw 7.9, epicenteredaround the Car Nicobar Island also caused tsunami waves
and flooded large area of coasts of the Indian Ocean while
no waves were recorded at the tide stations on the Burmacoast (Berninghausen, 1966; Ortiz and Bilham 2003).

3. Past Earthquakes Documented in Myanmar
To forecast the future, it is essential to know what
has happened in the past. The historical and past scientificrecords revealed that 1750± and 1762 events affected thewestern coast of Myanmar (Chhibber 1933, Heck 1947,
Berninghausen 1966) (Fig. 1).
Chhibber (1934, p.48) described the 1762
earthquake as follows.
The earliest earthquake on record, which affected Burma,
took place at 5 p.m. on 2nd April, 1762. It was very violent
and destructive, and was felt all over Bengal, Arakan etc.,
chiefly and more severely in the northern part of the eastof coast of the Bay of Bengal. The effects of thisearthquake, causing, according to Halsted, and elevationof the coast of Arakan, are given in the sequel, though
Mallet was inclined to be sceptical about his observations.
About the ca. 1750 earthquake, Chhibber (1934,
pp. 66-67) stated that
There is unmistakable evidence of recent upheaval in the
Arakan Division, and this is believed to have alternatedlocally with periods of relative quiescence orsubmergence, which is always difficult to identify…… A
map of the latter (Flat Island) that accompanies Captian
Halsted’s paper shows the present island to consist of

4. Paleoseismological Survey
We targeted to investigate tsunami deposits andcoastal land level changes with respect to the current sea
level. Recent research tools on the identification ofearthquake recurrency are chronological andsedimentological studies of the coastal sediments
commonly found in tidal flat and coastal lagoon, because
earthquake and tsunami events along the subduction zone
occasionally promote the tsunami deposit and/or land levelsubsidence or uplift. This coseismic subsidence or uplift ofthe coast causes the inter-layering of marine and nonmarine sediments along coast. As an example, earthquake
induced tsunami deposit found at the Mochirippu lake
along the Pacific coast of eastern Hokkaido wereintercalated with tidal peat and mud succession, andradiocarbon age of the sand layer confirmed the evidence

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Paleoseismological field survey along the western coast of Myanmar

for the 17th century earthquake occurred along the Kuril
subduction zone (Sawai et al. 2004).
We further planned to investigate geomorphologyof the coastal land form. It includes investigation ofmarine terraces, coral reef and coral micro atoll. Height ofmarine terraces is measured by level profiling of suchlandforms. Presence of emerged coral reef and microatoll
along the coast could give a firm evidence for the verticalcrustal movement with respect to sea level because theirlimitation for living environment is limited under sea
surface. Dating records of annual growth ring of coralmicroatoll were best implied to coseismic uplift of the
giant December 2004 Sumatra earthquake and pastearthquake recurrence along the west coast of Sumatra(Natawidjaja et al., 2004, 2006).
By utilizing the available geographic map(Tactical Pilotage Map, 1:500,000; Defense Mapping
Agency Aerospace Center, 1989) and satellite images(ASTER taken at 2003-11-21T04:31:26Z), survey areas
for the tidal flat, coastal lagoon and coral reef exposure arechosen. The survey areas fall on surrounding regions of
the two cities of Rakhine state, the western coast of
Myanmar, namely Sittway and Thandwe cities (Fig 2).
Five localities around these two cities were investigatedduring the survey period of 10 days (February 4-13, 2006).
These are
1. Lagoon at the west coast of Sittway City
2. Coast of Myengun island, Sittway City
3. Coast of Tandin island, Sittway City
4. West coast of Shwehle Town, Thandwe City
5. Coast of Lontha, Mawyon and Thabyu Chaing,Thandwe City
Portable GPS for recording survey localities, autolevel and hand-held laser instrument (Impulse 200LR;
Laser Technology Inc.) for measurements of terrace
profile, handy corer and geoslicer for sediments sampling
and observation, were used in this survey. In addition, weinvestigated tsunami heights at five survey points due to2004 Sumatra-Andaman earthquake, by conventional
Rise-and-Fall method.
Total of 29 survey points, numbered MM0601 to
29, with description of survey date, locality name, survey
point number, GPS location, type of survey (TD: Tsunami
Deposit, TH: 2004 Tsunami Height, MT: Marine Terrace
and CR: Coral Reef) and collected samples are listed inTable 1. We hereby describe the details of survey from
north to south (see Fig. 1).

coast of Myanmar including Sittwe city and its
surrounding areas fall on the tropical monsoon climate andreceive very high mean annual rain fall with > 2500 mm/
yr (Bender 1983). Because of the tropical monsoon
climate storm surges, such as cyclones, occurred several
times in the past and, the coastal regions of Sittway andKyaukphu cities have been flooded by large storm surgesof cyclones (Murty et al. 1986). Coastal zones near by andaround Sittway city have broader area than other regionsof western coast of Myanmar, up to ~ 70 km near the city,
due to extensive detritus fans and fluvial sediments
brought down from the north by the rivers Mayu, Kaladan
and Lemro (Bender 1983). We choose the coastal lagoon,
the west coast of Sittway city, to investigate tsunami
deposit and Myengun and Tandin islands, the surrounding
regions of Sittway city, to investigate the marine terraces
and uplifted coral reef.
5.1 Survey at Lagoon, West Coast of Sittway City
(MM0601 – 10, MM0619 – 22)
Survey was done for investigation of tsunami
deposit in the lagoon of the west coast of Sittway city (Fig.
3). For two days, coring and trenching of lagoon sediments
were conducted. Total of 14 survey points were
investigated for tsunami deposits and accounts for the2004 tsunami height were taken at three of them (Table 2).
The lagoon trends NNW-SSE and is ~ 15 km long and ~1 km wide. Muddy bioturbated sediments, dead trees andpartially intercalated lens-shape sand were collected
mainly in the southern parts of the lagoon (Fig. 4 A-D and5), while sandy sediments are predominant in the northernparts. In the central part, 7 cores (MM0601, MM0603 –09) were taken in NE-SW traverse across the lagoon and 4cores were collected in the southern part (MM0610,
MM0619 – 21). Sediment sections in the central andsouthern portion were predominantly soil and mud, and insome cores, sandy mud (Fig. 5) with shell fragments andplant’s stems and leaves were characterized. A few
probable event sand layers were intercalated into mud at
MM0601, MM0609 and MM0620-21.
MM0601: At the survey point in the same lagoon near
The-Chaung Village, we collected a 1.0 m long coresection of silty sand with shell fragments capped by recent
soil (0 - 0.08 m) and very coarse sand (0.78 - 1.0 m) at thebase. However between 0.45 - 0.53 m, a coarse grain sandlayer, probably event deposit, was observed with sharpbasal contact with the lower silty sand layer.
For the height of 2004 Sumatra tsunami, we mademeasurement based on the account of the eyewitness. The
measured tsunami height was 1.49 m above sea level at
the time of survey (2006 February 05; 16:15). The tidelevels at the time of measurement and at tsunami can be

5. Survey at Sittway City and Its Surrounding Regions
Sittway city is the capital of Rakhine state which
covers almost the western coast of Myanmar. The western

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Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tuncomputed to be 1.47 m and 1.68 m above datum
respectively by using WXTide32 program. Then actual
tsunami height is converted to be 1.28 m (Table 3).
MM0602: At the northernmost survey point of the lagoon
near Ohndaw village, the section was totally covered bysand (Figs. 4C and D). Here we could also grasp theinformation of height of 2004 Sumatra tsunami. Measured
tsunami height was 2.7 m at the time of survey (2006
February 05; 17:45), and actual tsunami height wasestimated to be 2.88 m.
MM0603: The survey point locates ~ 200 m west of
MM0601 and a 0.9 m long core composed of bioturbatedfine sand at the top (0 – 0.4 m) and muddy sand layer (0.4
– 0.9 m) at the base was taken. Tiny plant stems and leaves
were observed in the muddy sand layer.
MM0604: At this survey point, ~ 130 m SW from
MM0603, a (0.55 – 0.95 m) long sediment section wascored. The observed lithofacies are mud layer (0.55 –0.6 m) at the top and fine to medium sand (0.6 – 0.95 m)layer at base.
MM0605: About 400 m SW of MM0604, a core was taken
and all the section was composed of sand.
MM0606: At 100 m south of MM0605, a core section (0 –0.6 m) was fully characterized by sand and a fragment ofplant’s stem was observed at the depth of 0.4 m. The
survey point was located near a small stream channel
probably caused by the low and high tide flowage.
MM0607: The survey point was an about 1 m deep trench
being dug by the locals in making embankment of ponds
for shrimp hatcheries. (Fig. 4A and B). The trench was
located about 100m southeast of MM0604. The lithofacies
observed at the trench wall were brown bioturbated sandy
mud intercalated with several centimeters long lensshaped sand at upper part (0 – 0.4 m) and grayish muddy
sediments with fragments of plant’s stem and roots at thebase (0.4 – 0.85 m). Level measurement gave that theelevation of the top of trench wall is 0.58 m above the sea
level at the time of investigation . The sea level at 2006
February 06; 14:40 is 0.67 m and mean sea level is 1.48 m,
hence the top of trench wall is below 0.23 m below themean sea level.
MM0608: At about 70 m southwest of MM0601, 1 meterdeep core section was taken. Soil (0 – 0.1 m), muddy sand(0.1 – 0.5 m) and beach sand (0.5 – 1.0 m) were observed.
Fragments of plant’s stem were found at the depth of
0.55 m.
MM0609: The survey point is the same location as
MM0601 and was re-cored by handy geoslicer for theconfirmation of the event deposit (observed at 0.45 –0.53 m in MM0601). A section (0.3 – 0.8 m) by handy
geosclicer was observed. The lithofacies are nearly
identical to the core section of MM0601.

MM0610: The survey point is one of the four points
investigated in the southern part of the lagoon (Fig. 3) near
Bazar village, characterized sand layer (0 – 0.14 m) at thetop, bioturbated mud layer with lens-shaped sand (0.14 –0.7 m) in the middle and grayish mud layer (0.8 – 1.0 m)
at the base.
MM0619: 1 m depth sediment section was cored at thesurvey points at Barsar village, very close to MM0610,
and composed of a mud layer with leaves and stems ofgrasses (0 – 0.1 m) at the top, bioturbated mud layer (0.1 –0.4 m) in the middle and mud layer with lens-shaped sand(0.4 – 1.0 m) at the base. Plant’s roots and stems areobserved at 0.45 m and 0.85 m.
MM0620: A 1.3 m long core was taken at the survey
point, about 130 m north of MM0619, of Barsar village.
The lithofacies until the depth of 1.05 m were identical tothose of MM0619 and a sand layer with few mud clasts
was observed at (1.05 – 1.3 m).
MM0621: Survey point very close to MM0620 was coredwith depth to 1.5 m to investigate a deeper section of
MM0620. A sand layer was observed at (1.42 – 1.5 m).
Plant’s stem above the basement sand at 0.85 m wascollected for radiocarbon sample. It was measured as280-170, 150-10 cal yrBP (Table 2),
MM0622: Height of 2004 Tsunami was measured basedon eyewitness’ accounts at the survey point, with thelocality name of Barsar village. Measured tsunami heightwas 2.3 m above sea level at the time of (2006 February
06; 10:00), and actual tsunami height was estimated to be
2.1 m.
5.2 Survey at Myengun Coast, Sittway city (MM0611 –16)Myengun locality is on the west coast of an
isolated island located a few kilometers southeast of
Sittway City. On Myengun coast, investigation of tsunami
deposit, marine terrace and coral reef were conducted at 6
survey points (MM0611 – MM0616). Contrast to thelagoon on the west coast of Sittway City, sediments were
mostly very loose sand (probably beach sand) with very
tiny fragments of shell. At the higher elevation of thecoast, on the marine terrace, sediments were quite dry andthe ground surface was too hard to drill core sections. We
could not find event deposit in this area. Profiles of marine
terraces and a sand bar were taken by auto level and laser
ranging instrument. Information on tsunami height of the2004 Sumatra tsunami was also collected at one of thesurvey points.
MM0611: At this survey point, height of the 2004 tsunami
was obtained as the measured height, 1.95 m, at the timeof survey (2006 February 07; 11:00). Actual tsunami
height was estimated to be 1.23 m.

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Paleoseismological field survey along the western coast of Myanmar

MM0612: From this survey point on the tidal flat on theeast side of Myengun coast (see Fig.7B), 0.4 m depth of
sediments were able to core. The sediments are mud layer(0 – 0.15 m), mud with plant’s stems (0.15 – 0.25 m), andsand with tiny shell fragments at the base (0.25 – 0.4 m).
MM0613: The sand bar was observed at this survey point
and a topographic profile was taken by level measurement.
The height of sand bar is ~ 2.0 m above sea level at thetime of survey (2006 February 07; 12:30) (Fig. 7).
MM0614: The survey point located on a terrace and a 0.3
m long sediment core section was taken. The observed
sediment section was mud with tiny shell fragments (0.14– 0.3 m).
MM0615: The point was several tens of meters to theinland from MM0614. Several large sandstone boulders
with eroded shell imprints were investigated there.
MM0616: At this survey point, marine terraces of threelevels were recognized as the lower terrace (~ 250 m inwidth and ~ 2 m in height), middle terrace (~ 200 m inwidth and ~ 7.5 m in height) and the upper terrace(~ 200 m in width and 19 m in height) (Fig. 8). Samples offossil corals found on the surface of the upper terrace(~ 13 m in height) were collected for radiocarbon dating.
They were dated to between 3030 and 2650 cal yBP (Table
2).

6. Survey at Thandwe City and Its Surrounding
Regions (MM0623 –29)
Thandwe City is a resort city located about
250 km south from Sittway City. We chose the coast of
Shwehle Town to investigate the tsunami deposit andcoasts of Lontha, Mawyon and Thabyuchaing villages forinvestigation of uplifted coral reefs to identify land levelchanges (Figs. 11 and 12). However, no significant
evidence, either tsunami deposits or uplifted coral reefs, toidentify the past earthquake evidence, was found. The
height of 2004 Sumatra tsunami was obtained at MM0624.
6.1 Survey at Shwehle Town, Thandwe City (MM0627–
28)
A marine terrace was investigated at the survey
point, west coast of Shwehle Town. The terraces consistsof two levels; the lower terrace (~ 150 m in width and 3 m
in height) and the upper terrace (~ 150 m in width and 4.5
to 5.5 m in height) (Fig. 11C).
MM0627: Two trenches 0.4 m and 0.44 m in depth were
dug up on the surface of the lower terrace to investigate
tsunami deposit. No tsunami deposit was found and theobserved sediments were only dry recent soils and mud.
MM0628: One trench with the depth of 0.3 m was dug up
on the surface of the upper terrace. No tsunami deposit
was found and the observed sediments were only dry
recent soils and mud (Figs. 11D and E).

5.3 Survey at Tandin Coast, Sittway City (MM0617 &MM0618)
Tandin coast is ~ 50 km southeast from the
Sittway City. We were able to make investigation ofmarine terraces and coral at two survey points (Figs. 9 and
10). Three levels of marine terraces were recognized and a
profile was made by auto level and laser ranging
measurements.
MM0618: Marine terraces observed at north survey pointof Tandin coast have three steps of lower, middle andupper. The lower terrace with 80 m in width was raisedwith 1.0 m in height above sea level. Then, middle terrace(~ 150 m in width and ~ 4.0 m in height) and the upperterrace (~ 60 m in width and ~ 6.5 m in height) wererecognized. Below the lower terrace, wave cut bench(~ 20 m in width and ~ 0.5 m in height) is formed atpresent time (Figs. 10A and B)).
MM0617: Survey point is several hundreds meter southfrom MM0618. The lower terrace (~ 20 m in width and
1.0 m in height), the middle terrace (~ 20 m in width and2.5 m in height) and the upper terrace (~ 30 m in widthand 5.5 m in height) were identified. Coral fragments were
found on the surface of the upper terrace (~ 5 m in height)(Figs. 10C and D). Three broken pieces of fossil corals
were collected for radiocarbon dating. They were dated to
between 2720 and 2480 cal yBP (Table 2) (Fig. 8D).

6.2 Survey at Lontha, Mawyon and Thabyuchaing(MM0623 – 26, MM0629)
MM0623 – 26, MM0629: No coral reef was found out
except fragments of dead corals, probably recent in age. At
MM0626 table-shaped coral with 0.5 m in width wasobserved and the elevation of the table coral was above
0.18 m above sea level at the time of measurement (sealevel at 2006 February 10; 12:10 is 0.96 m and mean sea
level is 1.48 m, and hence the elevation coral was 0.34 m
below mean sea level) (Figs. 12A and E). At MM0624
measured tsunami height was 1.6 m at the time of survey(2006 February 10; 9:00), and actual tsunami height wasestimated to be 0.85 m.
7. Summary of Survey
Total of 29 survey points around Sittway andThandwe cities along the western coast of Myanmar were
investigated to find out the evidences of past subduction
zone earthquakes.
7.1 Tsunami Deposit
Along the west coast of Sittway City, we madecoring on several survey points in the lagoon to find out

175Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tuntsunami deposit. The lagoon was mostly characterized bymuddy sediments with sand lensoids in some places.
These sand lenses, a few centimeters to tens of centimetersin length, are possibly of marine origin, and are thought tobe deposited by storm or tsunami. In MM0601 a sandlayer was supposed to be of event deposit because sharpboundary on its base could be considered one of thecharacteristics of abrupt deposition due to storm or
tsunami. In core sections of MM0620-21, several sandlayers were recognized but But no correlation of suchsand layer was found in the cores collected around theMM0601. Most of the core sections do not provide
significant depositional layering and lithofacies, and insome cores parts of woods and man-made materials are
mixing in the upper coverage (0 ~ 0.4 m) of sediments. It
could be considered that the sediment section (coverage 0~ 0.4 m) of the lagoon will have to be suffered by artificial
effects. Age of a sample of plant’s stem above thebasement sand from MM0621 core was measured as after
280 cal yBP (Table 2), and it reveals that the lagoon wasformed since or before that time.

Myengun coast and ~ 5 m at Tandin coast. Thus elevationsof terraces were higher in the oceanward (e.g. Myengun
coast) than continentward (e.g. Tandin coast) (Fig. 14),suggesting probably continentward tilting of these coastal
areas. We believe that the terraces are the records of past
subduction zone earthquakes along the plate boundary offwestern coast of Myanmar.
8. Conclusions and Future Work
Three main remarks can be conclusively drawn
based on the investigation of 29 survey points ofgeological and geomorphological evidences along thewestern coast of Myanmar.
1. We aimed to find out tsunami deposit and uplifted
coral reef (atoll) due to past earthquakes, 1750 andothers. But no clear evidence for tsunami deposit anduplifted coral reef system, except fragments of fossil
coral, was found for identification of the inferred
land level changes due to past earthquakes.
2. Three levels of emerged terraces were found,suggesting that episodic uplifts occurred along thecoast. Based on radiocarbon age of corals found on
the upper most terraces, the western coast of
Myanmar suffered three uplift events during the last~ 3000 years. And continentward crustal tilting could
also be considered.
3. Tsunami heights along the western coast of Myanmar
due to 2004 Sumatra-Andaman earthquake were <3.0 m.
More detailed fieldwork is needed to estimate
when the uplifts of marine terraces (higher, middle andlower terraces) occurred. Additionally, mapping the lateralextents of uplifted terraces is also needed to ensure thatthese terraces were formed by tectonic activity associatedwith the subduction-zone earthquakes. Thus we plan tocontinue our survey on the western coast of Myanmar inearly 2007.

7.2 Tsunami Height
Based on local people’ accounts, we could alsocollect the information of tsunami heights along thewestern coast of Myanmar due to 2004 Sumatra-Andaman
earthquake at five survey points. The results were less than
3.0 m and are the same as those of the Tanintharyi coastand the Ayeyarwaddy delta (Satake et al., 2006) (Fig. 13).
7.3 Marine Terrace
Although no clear sedimentological evidences forthe past earthquake events were obtained, uplifted marine
terraces were recorded along Myengun and Tandin coasts
south of the Sittway City. At Myengun coast, three levelsof emerged coastal terraces were recognized with the
maximum height of ~ 19 m above mean sea level.
Similarly, marine terraces were investigated at the Tandin
coast ~ 30 km far south from the Myengun coast. In
Tandin coast, three levels of marine terraces at two sites
were investigated and the maximum height of the higher
terrace was up to 6 m at the northern site and up to 5.5 m
at the southern site. Based on the dating of the fossil coral
samples collected from the uppermost terraces ofMyengun and Tandin coasts, three uplift events occurred
during the past ~ 3000 yrBP (Table 2). Around Thandwe
City, we also tried to find out the uplifted coral reef toinfer relative sea level change. No reef system of corals
was found in investigation in four survey points.
The collected fossil coral samples from Myengun
and Tandin coasts have almost the same age of ~3000
yrBP, but their elevations are different as ~ 13 m in at

Acknowledgements
Support and encouragement form Myanmar
Earthquake Committee (MEC) and Myanmar Departmentof Meteorology and Hydrology (DMH) make this survey
trip end up successfully. For this, we greatly acknowledge
Director General U Tun Lwin (DMH), President of the
MEC, U Than Myint (Myanmar Engineering Society),scientists and staff from MEC and DMH. We also thankDr. Minoru Urai from Geological Survey of Japan forproviding us ASTER satellite images for the survey areas.
Financial support of the field survey was contributed bySpecial Coordinating Funds for Promotion Science andTechnology, from Japanese Ministry of Education, Sports,
Culture, Science and Technology.

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Paleoseismological field survey along the western coast of Myanmar

References

Avouac, J.-P. and Ward, S. N. (2006) Source
parameters of the great Sumatran megathrustearthquakes of 1797 and 1833 inferred from coralmicroatolls, Journal of Geophysical Research, Vol.
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Nielsen, C., Chamot-Rooke, N., Rangin, C. and
ANDAMAN Cruise Team (2004) From partial tofull strain partitioning along the Indo-Burmese
hyper-oblique subduction, Marine Geology, 209, p.
303-327.
Ortiz, M. and Bilham, R. (2003) Source area ad rupture
parameters of the 31 December 1881 Mw = 7.9 Car
Nicobar earthquake estimated from tsunamis
recorded in the Bay of Bengal; Journal ofGeophysical Research, Vol. 108, B4, 2215,
doi:10.1029/2002JB001941.
Satake, K., Than Tin Aung, Sawai, Y., Okamura, Y., Kyaw
Soe Win, Win Swe, Chit Swe, Tint Lwin Swe, Soe
Thura Tun, Maung Maung Soe, Thant Zin Oo, and
Saw Htwe Zaw (2006) Tsunami heights anddamage along the Myanmar coast from theDecember 2004 Sumatra-Andaman earthquake,
Earth, Planets, Space, Vol. 58 (No. 2), pp. 243-252.
Sawai Y., Satake, K., Kamataki, T., Nasu, H., Shishikura,
M., Atwater, B. F., Horton, B. P., Kelsey, H. M.,
Nagumo, T. and Yamaguchi, M., (2004) Transient
Uplift After a 17th-Century Earthquake Along the
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p. 1918-1920.
Sieh, K., Stebbins, C., Natawidjaja, D. H. and Suwargadi,
B. W. (2004): Mittigating the effects of large
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Eos Trans. AGU, 85(47), Fall Meet. Suppl,
PA23A-1444.
Socquet, A., Vingy, C., Chamot, R. N., Simons, W.,
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Kanbua, W., Srivichai, M. and Meesuk, V. (2005)
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deformation around Sagaing Fault, Myanmar,
Journal of Geophysical Research, 108 (B11),
doi:10.1029/2002JB001999.

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25, p. 187-232.
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Tactical Pilotage Map, 1:500,000, St. Louis,
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Fujii, Y. and Satake, K. (2007) Tsunami source of the 2004
Sumatra-Andaman Earthquake inferred form tidegauge and satellite data, Bulletin of SeismologicalSociety of America, in press.
Heck, N. H. (1947) List of seismic sea waves; Bulletin of
Seismological Society of America, Vol. 37.4,
p. 269-286.
Mallet, F. R. (1878) The Mud Volcanoes of Ramri and
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Matsutomi, H., Takahashi, T., Matsuyama, M., Harada, K.,
Hiraishi, T., Supartid, S. and Naksuksakul, S.
(2005) The 2004 off Sumatra earthquake tsunami
and damage at Kaho Lak and Phuket islands inThailand, Auunal Journal of Coastal Engineering,
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storm surge problem in the bay of Bengal, Progressin Oceanography, Vol. 16, p. 195-233.
Natawidjaja, D. H., Sieh, K., Ward, S. N., Cheng, H.,
Edwards, R. L., Galetzka, J. and Suwargadi, B. W.
(2004) Paleogeodetic records of seismic andaseismic subduction from central Sumatran
microatolls, Indonesia; Jurnal of GeophysicalResearch, Vol. 109, B04306, doi:10.1029/
2003JB002398.
Natawidjaja, D. H., Sieh, K., Chlieh, M., Galetzka, J.,
Suwargadi, B. W., Cheng, H., Edwards, R. L.,(Received: August 17, 2006, Accepted: September 11,
2006)
177

TD

MT, CR
MT, CR

92 º 50' 11.4"
92 º 50' 02.9"
92 º 50' 03.2"
92 º 50' 12.5"
92 º 50' 15.2"
92 º 50' 14.0"
92 º 52'17.0"
92 º 55' 06.4"
92 º 55' 15.3"
92 º 55' 12.7"
92 º 55' 01.0"
92 º 55' 08.2"
92 º 56' 08.3"
93 º 07' 58.3"
93 º 07' 56.1"
92 º 52' 17.1"
92 º 52' 12.9"
92 º 52' 06.4"
92 º 52' 54.1"
94 º 20' 14.8"

20 º 09' 12.9"
20 º 09' 02.6"
20 º 08' 55.9"
20 º 09' 07.2"
20 º 09' 21.7"
20 º 09' 23.9"
20 º 07' 24.7"
20 º 04' 57.7"
20 º 04' 59.2"
20 º 05' 04.2"
20 º 04' 28.4"
20 º 04' 27.1"
20 º 02' 21.3"
19 º 50' 26.7"
19 º 50' 40.2"
20 º 07' 25.4"
20 º 07' 26.9"
20 º 07' 27.7"
20 º 07' 12.0"
18 º 21' 47.3"

2006/02/06
2006/02/06

2006/02/06
2006/02/06

2006/02/06
2006/02/06
2006/02/07

The Chaung, Sittway

The Chaung, Sittway

The Chaung, Sittway

The Chaung, Sittway

The Chaung, Sittway

The Chaung, Sittway

MM0605MM0606

MM0607MM0608MM0609MM06102006/02/07

2006/02/07
2006/02/07

2006/02/08
2006/02/09
2006/02/09
2006/02/09
2006/02/09

Myengun coast, Sittway

Myengun coast, Sittway

Myengun coast, Sittway

Myengun coast, Sittway

Tandin coast, Sittway

Tandin coast, Sittway

Basar village, Sittway

Basar village, Sittway

Basar village, Sittway

Basar village, Sittway

MM0613MM0614

MM0615

MM0616

MM0617178

MM0618MM0619MM0620MM0621

MM0622

TD, MTTD

94 º 20' 56.3"
94 º 14' 42.0"
94 º 14' 45.9"
94 º 22' 56.1"

18 º 18' 43.3"
18 º 35' 50.7"
18 º 35' 53.3"
18 º 18' 05.9"

2006/02/10
2006/02/10
2006/02/10

Mawyon, Thandwe

Kyauk Phyu Maw, Thandwe

Kyauk Phyu Maw, Thandwe

Thabyu Chaing, Thandwe

MM0626

MM0627

MM0628MM0629

CR

C

C

C

C

S

S

C

C

S

S

S

S

S

S

S

S

Sample
Type

1

1

1

1

2

3

4

2

1

2

1

2

2

3

4

3

No. ofSample

16:30

12:10

9:00

10:00

9:30

15:35

12:30

17:00

12:30

11:00

15:06

14:40

13:30

17:45

16:15

Time atmeasurement
Tide at

0.62

1.62

1.23

1.48

1.36

0.58

1.04

0.87

0.65

0.95

0.76

0.62

0.51

1.86

1.48

measurement, mNote Survey type: TD – Tsunami Deposit, TH – Tsunami Height, MT – Marine Terrace, CR – Coral Reef; Sample type:C – Coral; S – Sediment; Values of tide level are takenfrom WXTide32 Program. Tide level for Sittway, Myengun and Tandin are referred from Sittwe station (92 º 54.00'E, 20 º 8.00'N ) and those for Lontha, Mawyon, Thabyuchaing
and Shwehle are from Andrew Bay station (94 º 21.00'E, 18 º 21.00'N).

2006/02/11

CR

94 º 20' 13.8"

18 º 14' 35.5"

2006/02/10

Mawyon, Thandwe

MM0625CRTH

94 º 20' 05.3"

18 º 14' 45.3"

2006/02/09
2006/02/10

Lontha, Thandwe

Mawyon, Thandwe

MM0623

CR

TH

TD

TD

TD

MT, CRTD

TD

MT, CR

TD

TH

TD

TD

TD

TD

TD

MM0624

2006/02/08

2006/02/07

2006/02/07

Myengun coast, Sittway

Myengun coast, Sittway

MM0611

MM0612

2006/02/06

2006/02/06

The Chaung, Sittway

The Chaung, Sittway

TDTD

92 º 50' 13.6"

TD, TH92 º 47' 17.4"

20 º 09' 16.6"

TD, TH92 º 50' 14.0"

20 º 09' 23.9"

SurveyType

Longitude

Latitude

20 º 11' 15.1"

2006/02/05

MM0603

Ohndaw, Sittway

MM0602

2006/02/05

Date

MM0604The Chaung, Sittway

Locality

MM0601

Stop

Table 1. Brief description of survey localities carried out along the western coast of Myanmar.

Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

UpperTerrace
Upper
Terrace
Upper
TerraceUpper

20 º 02' 18.6"N
92 º 56' 01.6"E
20 º 02' 18.6"N
92 º 56' 01.6"E
19 º 50' 45.0"N
93 º 08' 00.0"E
19 º 50' 45.0"N

MM0616,Myengun

Terrace (south)

179

MM0616, Myengun

Terrace (south)

MM0618, Tandin

Terrace (south)

MM0618, Tandin

Terrace (south)

92 º 52' 12.9"Eof Sittway City

Grass

BuriedBelow MSL

~ 1.0 m~ 5.0 m2.88
1.23

92 º 47' 17.4"
92 º 55' 06.4"
92 º 52' 54.1"
94 º 20' 05.3"

20 º 11' 15.1"
20 º 04' 57.7"
20 º 07' 12.0"
18 º 14' 45.3"

Ohndaw,
Sittway City

Myengun coast,
Sittway City
Basar,
Sittway City

MM0602

MM0611-29.37±0.20-0.54±0.12-1.56±0.16-1.19±0.17-5.31±0.16

δ13C ( ‰)130±202860±202830±203145±202925±20

Conventional
14
C age

40-10

120-70150-130230-210270-240

2705-2605

2680-2550

2970-2870

2735-2690

Calendar age
1σ(△R=0)(cal yr BP)

150-10280-170

0.85

1.6

2.3

1.95

2.7

1.49

Measured
Height, m(B)

9:00, 2006 Feb 10

10:00, 2006 Feb 9

11:00, 2006 Feb 7

17:45, 2006 Feb 5

16:15, 2006 Feb 5

Time ofMeasurement

1.26

1.48

0.95

1.86

1.47

Tide Level
Measurement, m(C)

PLD-5762

PLD-5761

PLD-5760

PLD-5759

PLD-5758

Lab Code

2.01

1.68

1.68

1.68

1.68

Tide Level
at Tsunami, m(D)

2720-2520

2700-2480

3030-2840

2755-2650

Calendar age
2σ (△R=0)(cal yr BP)

Note: Tsunami heights (A) are obtained by (B+(C-D)) (Satake et al. 2005, 2006). Tidal Level are computed by using WXTide32 program and tidal level for MM0624, Thandwe
city is taken from Andrew Bay (94 21.00'E, 18 21.00'N) whereas the others from Sittway city are taken from Sittwe station (92 54.00'E, 20 8.00'N). The tsunami arrival is
assumed to be at 11:30am on 2004 December 26, which is as same as the arrival at Ayeyarwaddy Delta (Satake et al. 2006).

MM0624

Mawyon,Thandwe City

1.28

92 º 50' 14.0"

20 º 09' 23.9"

The Chaung,
Sittway City

MM0601

2.1

TsunamiHeight, m(A)Longitude

Latitude

Stop

MM0622~5m~ 13 m~ 13 mElevation ofsampleabove MSL

Table 3. Tsunami heights along the western coast of Myanmar due to 2004 December Sumatra-Andaman Tsunami.

Terrace
Tidal Lagoon

93 º 08' 00.0"E
20 º 07' 26.9"N

MM0620, West coast

Coral

Coral

Coral

Coral

SampleMaterial

Locality

06020901

06020803

0602080206020703B

06020703A

Environment

Locality

SampleGPS
Location

Table 2. Radiocarbon dating results of samples collected from the western coast of Myanmar.

Paleoseismological field survey along the western coast of Myanmar

Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun
90˚E

30˚N

100˚E
Direction of plate motion
Strike-slip Fault
Sunda-Andaman Trench

India Bangladesh

Earthquake epicenter(Mw 6.0-6.9, 1976-2006)

Sagaing
Fault

20˚N

Earthquake epicenter(Mw 7.0-7.4, 1976-2006）

Eurasia
Plate
MyanmarThai

Earthquake (1750± and 1762 )Burma
Microplate

Earthquake source (1941)
Earthquake source (1883)

10˚N

AndamanRidge

Earthquake source (1847)
Sunda
plate

Earthquake epicenter andsource (Mw 9.1, 2004
December)

IndoAustralian
Plate

Earthquake epicenter andsource (Mw 8.7, 2005 March)
Earthquake source (1861)

0˚

Fig. 1. A map showing tectonics and past earthquake and tsunami eventsin and around Sunda-Andaman Trench. Earthquake data for theperiod of 1976-2006 are referred as of Harvard CMT Catlalog,
others are referred as Chhibber (1934), Heck (1947), Berninghausen(1966), Ortiz and Bilham (2003) and Sieh et al. (2004).

92˚48'E93˚00'E

93˚12'E
90˚E

100˚E

30˚N
20˚12'N

Sittway City
West coastof Sittway city

20˚00'N

Myanmar

Myanmar

20˚N

Myengun
coast

10˚N
92˚E
22˚N

Tandincoast

19˚48'N

94˚24'E

st

oa

20˚N

nc

ter
es
W

94˚12'E

94˚E

Thandwe City

ar

nm

a
My

coast

of

18˚36'N Shwehle

18˚N

Bay of Bengal

18˚24'N

Lontha,Mawyon andThabyuchaingcoasts16˚N

18˚12'N

Fig. 2. Survey areas of the western coast of Myanmar. Paleoseismologicalsurvey was conducted two Cities of western coast of Myanmar,
Sittway and Thandwe and their surrounding regions.

180

Paleoseismological field survey along the western coast of Myanmar

92˚45'E

92˚51'E

MM0609MM060820˚12'N

MM0602

MM0601
MM0603MM0604[MM0607
MM0605MM0606
SittweCity

MM0621
MM0620MM0619MM0610[5 km

MM062220˚06'N

MM0607MM0605MM0606

MM0609MM0608MM0601
MM0603MM0604500 m

Fig. 3. Map showing survey points (red triangles; MM0601-10, 19-22) (left figure) andcoastal topography of lagoon from satellite image (ASTER) (right figure), the west
coast of Sittway city. Dotted lines, yellow and green, infer trends of the present
beach and the lagoon.

B

A

MM0607C
MM0607

D

Sandbar MM0602

Sandbar MM0602

Figure 4

Fig. 4. Survey at lagoon of west coast of Sittway city. A. Observation at road
construction trench (MM0607) B. Sediment section on the wall of trench,
C. Coring in the sand bar of the northern part of lagoon (MM0602) and D.
Sand bar.

181

182

MM0607

MM0619MM0610MM0621
MM0620MM0602

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

MM06220608

SL 0.58 m

MM0604[MM0607
MM0605MM0606
SittweCity

MM0603MM0601

MM0609MM060892˚51'E

}

0609

0.4

0.3

0.2

0.1

0.0

}

Soil

Sand

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

MM0619Radiocarbon Ageof a plant’ s stem
130±20 yr BP
280-170}cal yr BP
150-10MM0610core section

Disturbed

0612
Geoslicer

Sand (Event Deposit?)

0.8

0.7

0.6

0.5

Plant’ s stems, leaf and root

0503

0501

0502

0.4

0.3

0.2

MM0609

Mud

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Bioturbation

0610

0617

0.1

MM0608MM06010.0
SL
Feb 06
15:06

Sandy Mud

1.0

0.9

0.9

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.8

0603

0601

0602

MM0603

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Shell fragments

MM0604

Fig. 5. Columnar sections of core sediments at lagoon, west coast of Sittway city.

20˚06'N

20˚12'N

0.6

5 km

0606

0.4

92˚45'E

0607

0.3

0.5

SL
Feb 06
13:30

0.2

0.1

MM0606

[

0.0

1.42

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0904

0905

0901

0902

0903

MM0620MM0621Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

Paleoseismological field survey along the western coast of Myanmar

92˚51'E

92˚57'E

A

B
Sittwe City

MM061320˚06'N

MM0612

Profile of Figure 7

MM0611
MM0614
MM0615
MM0616

Profile of Figure 8

5 km
20˚00'N

Fig. 6. A. Map showing survey points (red triangles; MM0611-16) (left figure), and B. coastal topography
from satellite image (ASTER) (right figure) of Myengun coast, Sittway city, Green lines indicate theprofiles of marine terraces (see Figures 7 and 8) where leveling measurement are made.

Elevation above Mean Tide
Level, cm

MM0613, Myengun coast (north), Sittwe city
250
200
150
100
50
0
-50

0
A

Sand Bar

West

East

-100

50

100

150

200

Horizontal Distance, m

B

C

MM0612
0.0

Mud
0.1

0.2

Sand
with tiny shell

0.3

fragments

0.4

Fig. 7. A. Cross sectional profile of sand bar measured at MM0613, Myengun coast (north),
Sittway city, B. Sediment coring at MM0-612 and C. Columnar section of observed
core section at MM0612.

183

Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

A

B

Surface of upper terrace

Surface of middle terrace
Overview of terrace at Myengun coast (south)
Myengun coast (south), Sittwe city, MM0616
C
Elevation above Mean Tide
Level, cm

Upper Terrace
2000
1800
1600
1400
1200
1000
800
600
400
200
0
-200

Middle Terrace
Lower Terrace~ 13 m

East

West
0

Radiocarbon Ageof coral fossil
2755-2650 cal yr BP
3030-2840 cal yr BP

100

200

300

400

500

600

700

800

Horizontal Distance, mD

DCoral fossils collected from upper terrace

Fig. 8. A, B. Photo of terrace observed at Myengun coast (south), C. Cross sectional profile
of terrace and D. Coral fossils collected from the upper step of the terrace. Star
symbols on profile indicate the elevation of collected dead coral samples.

93˚06'E
19˚54'N

93˚12'E

MM0617
MM0618

Profiles of Figure 10

Tandin Coast,
19˚48'N

Sittwe city

5 km

Fig. 9. Map showing survey points (red triangles; MM0617-18) (left figure) and coastal topography
depicted from satellite image (ASTER) (right figure) of Tandin coast, Sittway city.

184Paleoseismological field survey along the western coast of Myanmar

Tandin Coast (north), Sittwe city, MM0617
Elevation above Mean Tide
Level, cmA
800

Upper Terrace

700
600

Middle Terrace

500

Lower Terrace

400
300
200
100

Wave-cutTerrace

0

East

West

-100
0

100

200

300

400

500

Horizontal Distance, mC

BMM0617 Terrace at Tandin coast (south)

MM0618 Terrace at Tandin coast (north)Tandin coast (south), Sittwe city, MM0618
Elevation above Mean Tide
Level, cm

D

Upper
Terrace600
500

MiddleTerrace

400
300

Lower
Terrace

200

~5m

100
0
-100

East

West

-200
0

Radiocarbon Ageof coral fossil
2700-2480 cal yr BP
2720-2520 cal yr BP

50

100

150

200

250

Horizontal Distance, mFig. 10. A. Cross sectional profile of terrace at Tandin (north), B, C. Photos of terrace at Tandin(north) and D. Cross sectional profile of terrace at Tandin (south). Star symbols on profile
indicate the elevation of collected dead coral samples.

185

Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

94˚12'E

94˚18'E

A

B
MM062818˚36'N

MM06275 km
18˚30'N

Shwehle coast, Thandwe city,MM0627
Elevation above Mean Tide
Level, cm

C
600

Upper Terrace

500

Lower Terrace

400
300
200
100
0

West

East

-100
0

50

100

150

200

250

300

350

Horizontal Distance, mE
D

MM0628Terrace at Shwehle coast

Fig. 11. A. Map showing survey points (red triangles; MM0627-29) B. Coastal topography fromsatellite image (ASTER) of Shwehle coast, Thandwe city, C. Cross sectional profile ofterrace at Shwehle, Thandwe city, D. Photo of terrace at Shwehle, and E. Dry muddy
sediments observed (MM0628) trench on the lower step of terrace, Shwehle coast.

186

Paleoseismological field survey along the western coast of Myanmar

94˚18'E

94˚24'E

A

MM0623B

Lonthacoast

18˚21'N

MM0626
MM0629 Thabyuchaingcoast

Mawyoncoast
MM062518˚15'N

5 km

MM0624C

D

Level measurement at MM0626

Coral fossil found at MM0624
E

F

Coral fossil found at MM0626

Coral fossil found at MM0624

Fig. 12. A. Map showing survey points (red triangles; MM0623-26, 29), B. Coastal topography from satellite
image (ASTER) of Lontha, Mawyon and Thabyuchaing coast, Thandwe city, C, E, F. Coral fossils
found at Mawyon and Thanbyuchaing coasts (MM0624 and 26), D. Level measurement at MM0626.

187

Than Tin Aung, Yukinobu Okamura, Kenji Satake, Win Swe, Tint Lwin Swe, Hla Saw, and Soe Thura Tun

95˚E
20˚N

100˚E

0

5

15

20

20˚N

Myanmar (2006 February）
This suvery

Myanmar

15˚N

10

Thai

15˚N

Myanmar (2005 March)
Satake et al. (2006)

10˚N

10˚N

Tsunami sourceof 2004 December
Earthquake(Fujii and Satake
2006, in press)

Matsutomi et al. (2005),
Satake et al. (2005),
Tsuji et al. (2006)

Thailand

5˚N

5˚N

0

5

10

15

20

Height of 2004 Sumatra Tsunami, m

Fig. 13. Tsunami heights due to 2004 Sumatra-Andaman earthquake along Myanmar and Thai
coasts (Matsutomi et al., 2005; Satake et al., 2005; and Tsuji et al., 2006). Green color
data (< 3.0 m) of the western coast of Myanmar are obtained from this survey.

92˚48'E93˚00'E

93˚12'E

20˚12'N

Sittway City?

Myengun (~ 13 m)
20˚00'N

Tandin (~ 5 m)?

19˚48'N

10 km

Fig. 14. Schematic illustrations of tectonically active belt inferred fromthe distribution and elevation of marine terraces at Myengun
and Tandin coasts, Sittway city, western coast of Myanmar.

188