Journal of Natural Disaster Science, Volume 28, Number 1, 2006, pp35-41

Reconnaissance report of the 2004 Great Sumatra-Andaman, Indonesia, Earthquake– Damage to geotechnical works in Banda Aceh and Meulaboh –Tetsuo TOBITA1, Susumu IAI1, Banta CHAIRULLAH2 and Wimpie ASPER3
1
Disaster Prevention Research Institute (DPRI), Kyoto University
2
Syiah Kuala University, Indonesia
3
Badan Pengkajian dan Penerapen Teknologi (BPPT), Indonesia(Received for 1 Dec., 2005 and in revised from 13 Sep., 2006)

ABSTRACTOne of the largest earthquakes in our history occurred at 7:58AM (local time) on December 26 2004, off thewest coast of Northern Sumatra Island, Indonesia (Mw 9.3). The earthquake triggered a huge tsunami along thecoastlines of the Indian Ocean and caused a huge number of casualties. From March 1 to 6, 2005, reconnaissancewas conducted in the region of Banda Aceh and Meulaboh, Indonesia, where strong shaking and tsunamis wereobserved. The primary objective of reconnaissance was to investigate and record damage mainly due to strong
motions and to estimate the seismic intensity in the region. This paper reports on the damage to earth structures,waterfront structures, and roads washed away by tsunamis. Eyewitness evidence of liquefaction in Banda Aceh,
about 250 km away from the epicenter, was likely caused by the strong shaking of Mw 9.3. In Kuala Bubon village located about 15 km north of Meulaboh, settlements of embankments attached to bridge abutments collapsed
just after the earthquake and before the arrival of the tsunami, so villagers could not use motorcycles or bicycles
to evacuate. Lessons must be learned from this devastating earthquake, and disaster mitigation improved.

1. INTRODUCTION
1.1

Background on Research
One of the largest earthquakes (M w 9.3) in our history
occurred at 7:58AM (Local time) on December 26 2004, off thewest coast of Northern Sumatra Island, Indonesia (Fig. 1)(Kanamori, 2006). The rupture started off the north of the Simalur
Island and spread over 1,300 km by propagating northward at
roughly 2.8 km/s for approximately 8 minutes (Ishii et al., 2005).
The great earthquake triggered a devastating tsunami that struck
countries bordering the Indian Ocean; Indonesia, Sri Lanka, India,
Thailand, Malaysia, Myanmar, Maldives, Bangladesh, Somalia,
Kenya, Tanzania, and Seychelles. A total of 233,000 persons havebeen reported killed or missing (April 2005). Although theIndonesian meteorological agency had installed a seismometer in
Banda Aceh about 250 km away from the epicenter, the strong
motion of the main shock was too large for the seismometer torecord its maximum amplitude.
Considering the size of the event, the effects of strong motion
were expected to be devastating in cities or villages on the west
coast Sumatra Island. To investigate and record the damage andestimate the seismic intensity in the region, a reconnaissance team
(Leader: Prof. Hirokazu Iemura, Kyoto University) was organized
to survey the region of Banda Aceh and Meulaboh, Indonesia,
from March 1 to 6, 2005. The seismic intensity estimated based on
the results of a questionnaire survey of 381 respondents in Banda
Aceh was 5+ to 6- on the JMA seismic intensity (corresponds to

MMI = VIII) (Honda et al., 2005). The level of intensity seems to
be consistent with the damage in the area. However, it was difficult to estimate how many buildings collapsed as a result of thestrong motion because tsunamis swept almost everything away
except the foundations of houses.
Damage caused by tsunamis has been well documented byresearchers and related organizations all over the world (e.g., Iwan,

KEY WORDS: 2004/12/26, Sumatra, Earthquake, Tsunami, Geotechnical works

Fig. 1

Epicenter of the 2004 Great Sumatra-Andaman Earthquake

36

T. TOBITA , S. IAI, B. CHAIRULLAH AND W. ASPER

2006; Kawata et al., 2005). However, few studies have reported
on damage due to the strong shaking because the affected area waslimited to the west coast of Sumatra Island (Saatcioglu et al.,2006). Sengara et al. (2006) reports geotechnical engineering
aspects of building and infrastructure damage and emphasizes theneed for a seismic microzonation study to identify the spatial variability of strong ground shaking for reconstruction and future planning of affected cities.
This report focuses on the damage and performance of geotechnical works, such as earth structures, waterfront structures androads in Banda Aceh and Meulaboh areas. The major feature ofdamage in these areas is the combined hazards in addition to thehydrodynamic effects of the tsunami.
2. BANDA ACEH REGIONThe City of Banda Aceh is located at the northern edge of
Sumatra Island (Fig. 1). It is a low-lying area underlain by a
Holocene fluvial formed by Aceh River (Fig. 2) and estuarine
deposition. The city area stretches over 20 km from east to west
and 10 km from north to south. The surface and subsurface geology in the area is classified mainly as silt and clay, and sanddeposits were found on the right bank of Aceh River near the
grand mosque and coastline (Fig 2) (Wafid, 2005). Back marshes
used as shrimp farms are typically located behind the sand dunes

Fig. 2 Inundated area of Banda Aceh (DLR, 2005)

Fig. 3 Soft-story (1st story) collapse of a 5-story buildingthat form the coastline of Banda Aceh. Buildings or houses located from 3 to 5 km inland were affected by a tsunami as shown in
Fig. 2. The height of the tsunami in Banda Aceh ranged from 5 to
30 m (Tsuji et al., 2005). The inundated area is shown with ablack line with small arrows in Fig. 2.
As the city was built on predominantly soft soil, large RC
structures such as government and private buildings, shopping centers, hospitals and hotels (Fig. 3), whose natural period was relatively long, were damaged by strong motion. However, it should
be noted that damage to those buildings varied from total collapse
to minor damage depending on the type of foundation, local
ground conditions and spatial variation of strong ground motions.
The sharp contrast in the damage that occurred in the coastal andinland hilly area indicates that the soft ground conditions might
have been a significant factor in the damage to buildings in the
coastal area of Banda Aceh.
2.1 Loss of coastlines
The coastlines of Banda Aceh receded several hundred meters
after the tsunami (Fig. 4). Houses located on sand dunes near asmall fishery port at Ulee Lheue were completely swept away fromtheir foundations, and only wave-dissipating blocks remained
about 20 m off the seashore (Fig. 4). Based on measuring the difference in the water mark heights on the front and rear walls, thecurrent speed was estimated to be 25.2 km/h (Matsutomi et al.,Fig. 4

Aerial view of lost coastline near Ulee Lheue (taken on
March 4, 2005)

Fig. 5 Erosion behind the monument located at Ulee Lheue

RECONNAISSANCE REPORT OF THE 2004 GREAT SUMATRA-ANDAMAN, INDONESIA, EARTHQUAKE

2005). The inundation height of wave at Ulee Lheue Port was 12.2
m above the sea level. There was a local scour behind a monument standing near the fishery port and that might indicate thespeed of waves (Fig. 5).
Results of the reconnaissance indicate that the loss of landalong coastlines submerged into the sea was mainly due to erosion
by the hydrodynamic force of tsunamis; however, liquefaction also
likely contributed. According to the witness accounts of residents,liquefaction occurred before the tsunami struck. The sites consistof clean sand with an average particle size of 0.2 - 0.3 mm (Fig. 6).
The epicentral distance of the liquefied site in Banda Aceh,although it might not be the farthest site for this event, can be plotted in the figure developed by Ambraseys (1988) from the worldwide databse of shallow earthquakes (Fig. 7). As seen in Fig. 7,
the distance between Banda Aceh and an epicenter of 250 km foran earthquake of Mw 9.3 is consistent with existing findings.
2.2 Damage to levees
Aceh Water Sharing (Fig. 2) was constructed and completed
in 1992 in the eastern part of the city for flooding countermeasuresof the Aceh River, which meanders through the middle of the city.
The Overseas Economic Cooperation Fund (OECF) issued by thegovernment of Japan was used for the construction (CTII, 2005).
Although some covering soil of the jetty at the river mouth waseroded and unwoven fabrics to protect the levee were exposed, its
shape barely remained. The left bank of the levee was sand-Fig. 6

witched by the water channels, i.e., the Aceh River and the straightchannel that connected the marshlands of shrimp farms to the sea.
Significant damage was found on the left bank of the channel
about 1 km from the river mouth (Fig. 8), where marshland and thestraight channel merged. The levee’s body was laterally expandedin the transverse direction with remaining slope-protection stones,
and its crown settled near the water surface (Fig. 8b). Taking
account of its failure mode and the ground water depth at the site,
the damage could be due to loss of bearing capacity with liquefaction.
Considering that the right bank near the river mouth was moreeroded than the left bank, the tsunami waves might have initiallystruck the right bank and then been reflected to the left bank. This
may indicate a north-west incidence of tsunami waves at this location. The wave velocity was estimated from the collapsed bridgeat the river mouth of the Aceh Water Sharing. Its bridge girder
was supported by U-shaped concrete slabs attached on to the top ofpiers. When the tsunami struck the bridge girders, they pushed the
upstream side of the U-shaped slabs and as a result girders fell.
Based on the dimensions and strength of the concrete, the wave
velocity was estimated to be 12 km/h (Scawthorn et al., 2005).
2.3 Damage to the river protection wall of the fishery port at
LampuloLampulo, a small fishery port on the right bank of Aceh River,is located about 3 km north of the grand mosque (Fig. 2). At thetime of reconnaissance, small fishing boats were moored directly

Grain size distribution curve of sand samples collected at
Banda Ache and Meulaboh

(a)

(b)
Fig. 7

Maximum epicentral distance to liquefied sites Re and moment magnitude Mw(after Ambraseys 1988)

37

Fig. 8(a) Collapsed levee (left bank of the Aceh
Water Sharing), (b) Schematic view38

T. TOBITA , S. IAI, B. CHAIRULLAH AND W. ASPER

to less damaged river protection walls and fishermen were tradingfish.
At this location, river protection walls were constructed by Lshaped concrete slabs, whose height was 2 m and the width at thebottom was 1.5 m (Fig. 9 and 10). The walls were displaced
toward the river and in some parts totally collapsed. The material
behind these river walls was mainly sandy clay and interbedded
sands and gravels. Strong shaking and hydrodynamic force might
have caused the damage to the river walls.
2.4 Damage to the embankments for oil pipelines
At Malahayati, east of Banda Aceh, an embankment to support oil pipelines suffered minor damage (Fig. 11). Its main bodywas not cut or submerged in the sea, only its shoulders were eroded; however, pipelines were cut and dislocated to the other side of
the slope from their original position by tsunami induced force.
The embankment was jutting into the sea about 1 km, and near theend the pipeline was supported by piled piers. The pier andmachine cabin were undamaged.
Other remarkable damage at the site was that three oil storage
tanks out of nine were washed away by tsunamis due to the lack ofanchor bolts (Goto, 2005; Saatcioglu et al., 2006). One was relocated about 300 m west from its original position due to high tideof waves (Fig. 12). There were other relocated large objects, suchas a power generating vessel and large tankers, which might havedestroyed buildings and killed people in their path.
3. MEULABOH REGION
The suburbs of Meulaboh, the city closest to the epicenter,
were investigated. Due to the limited time and road conditions,reconnaissance was restricted within 45 km along the west coast of
Sumatra Island. The northernmost village was Kuala Bubon located about 15 km north of Meulaboh (Fig. 13 and 14) and the southernmost village was Kuala Tadu about 30 km south of Meulaboh.
3.1 Damage in Meulaboh
In the city of Meulaboh, although soft-story collapses of 4- to
5-story buildings due to strong shaking occurred, most buildings
made by RC or RC columns and beams were undamaged except
the first floors, which were scarred by floating debris.
Houses on the Ujoung Kalang peninsula (Coral Peninsula) in
Meulaboh, except the three-story RC structure of the police department, were totally destroyed and only debris remained. Floor slabs
of a pile supporting a passenger jetty were submerged into the sea
and only piles were left (Fig. 15).
Inland villages about 3 to 5 km north of the peninsula wereapparently undamaged by the strong shaking and the tsunamis. The
contrast between damaged and undamaged areas was striking inboth the appearance of buildings and the number of people killed.

Fig. 9 Failure of river protection walls at Lampulo

Fig. 11 Minor damage to the embankment for pipelines atMalahayati. Pipelines were dislocated.

Fig. 10 Tilted and dislocated L-shaped river protection at Lampulo

Fig. 12 Relocated oil storage tank at Malahayati

RECONNAISSANCE REPORT OF THE 2004 GREAT SUMATRA-ANDAMAN, INDONESIA, EARTHQUAKE

39

Fig. 13 Inundated area in Kuala Bubon and the direction of the aerial photograph shown in
Fig. 16 (DLR, 2005).

Fig. 15 Collapsed floor slab of a passenger jetty at a ferry port
in Ujoung Kalang, Meulaboh)Fig. 14 Satellite image of Kuala Bubon before the earthquake andtsunami (Google Earth)

3.2 Damage in Kuala Bubon village
Small villages are commonly seen near deltas in the westernpart of Sumatra Island. Seen from the air, river mouths were heavily eroded and red to brownish water was pooled in back marshes.
Houses along streets near the coastline were totally destroyed anddebris was scattered inland from the coastline.
Kuala Bubon is located on Holocene alluvial fan at the river
estuary of the Bubon River about 15 km north of Meulaboh. It
was a small village with a population of 1,500 before the tsunami.
A quarter of the population is thought to have been killed by thetsunami. Not only houses located near the beach, but also large

amounts of deltaic deposits were lost up to several hundred metersfrom the coastline (Fig. 16).
Survivors said that they saw an unusual white band of waves
gradually approaching from across the horizon, and they instinctively started to escape. Then, the tsunami struck and many villagers were swept away and some were caught by trees. One of
the two palm oil storage tanks by the beach was swept away anddumped in the woods about 3 km from its original position.
Splashed oil from the tank was found in the environment and may
have contaminated water in the area.
Eyewitness reports of water coming out from the cracked
floors of houses accounts for the occurrence of liquefaction in
Kuala Bubon. The soil was sandy and the grain size distribution
analysis of the sand collected in Kuala Bubon reveals the possibility of liquefaction (Fig. 6). The combined effects of liquefaction
and tsunami might be responsible for the submersion of land near
the deltas. Other eyewitness reports of liquefaction and sand boils

40

T. TOBITA , S. IAI, B. CHAIRULLAH AND W. ASPER

Fig. 18 One of the bridge abutments of a collapsed steel truss
bridge in Kuala Bubon
Fig. 16 Aerial view of Kuala Bubon and devastated road (taken on
March 2, 2005)

Fig. 19 Lost access road in Kuala Tadu
Fig. 17 Devastated road in Kuala Bubon. Photo was taken near the
crossroads shown in Fig. 13, 14 and 16

were found in Meulaboh and near a bridge in Kuala Tuha locatedsouth of Meulaboh. A mayor of a village near Ujoung Kalang in
Meulabo reported that black smelly water suddenly oozed from thefloor of his house up to the height of his knees.
3.3 Loss of main roads and damage to the bridges
A main road along the coastline of western Sumatra Island,
which connected Banda Aceh and Meulaboh, were devastated. In
the northern part of Meulaboh, because the road was constructed
either on sand dunes near beaches or lowland just behind the sanddunes, parts of the roads, especially near river deltas, were completely lost (Fig. 16 and 17). While in the southern part ofMeulaboh, the road was not damaged at all because it was constructed hundreds of meters inland from the coastline. After theearthquake, the main road was shifted to a narrow and unpaved
road running inland in between Meulaboh and Kuala Bubon. The
amount of traffic on the inland road, therefore, has been increased
and protection works of road shoulders have been implemented
using stones and mesh wires.
There was a 60 m steel truss bridge at the river estuary of
Bubon River (Fig. 14). Its girders fell and only two bridge abutments are left (Fig. 18). Wave force is responsible for the bridge

collapse. However, survivors said embankments to an access roadto the bridge abutment settled before the arrival of the tsunami as aresult of the strong shaking. People, therefore, could not escape byusing bicycles or motorcycles. The settlement may be attributed topoorly compacted soil or liquefaction. This has often occurred
after large earthquakes, e.g. vertical gaps at the edge of box culverts or near bridge abutments after the 2004 Mid Niigata
Earthquake, Japan (Tobita et al., 2005). In Kuala Tadu, where
similar type of damage was observed (Fig. 19), the people tied up
palm trees as a temporary bridge to fill the gap between the main
bridge girder and the access road. It takes tens of minutes to temporarily repair. Considering the time until being struck by
tsunamis, escape routes should be seismically stable.
4. CONCLUSIONS
The damage to and performance of geotechnical works understrong motion of the Sumatra-Andaman Earthquake, Indonesia (Mw9.3) have been mainly reported based on the field investigation
conducted from March 1 to 6, 2005, about 2 months after theearthquake. The team covered areas of Banda Aceh and Meulaboh
in northern Sumatra Island, Indonesia. Damage, particularly, on
low land, to earth structures, roads, and port facilities was found.
The findings are as follows:(1) The loss or submerging of land along the coastline in BandaRECONNAISSANCE REPORT OF THE 2004 GREAT SUMATRA-ANDAMAN, INDONESIA, EARTHQUAKE

(2)

(3)

(4)

(5)

Aceh was mainly a result of the hydrodynamic force oftsunamis, and a combined effect with liquefaction is suspected.
Considering the failure mode and surrounding environment,liquefaction might be the primary cause of damage to theembankments of the Aceh Water Sharing. The occurrence ofliquefaction at the distance of 250 km away from the epicenteris consistent with the existing data.
Damage to the river protection walls at Lampulo where clayeysoil was dominant might be due to the retraction force of thetsunami.
A major road between Banda Aceh and Meulaboh wasdestroyed. While a major road in the south of Meulaboh wasundamaged except for the bridges. This is because the road in
the north of Meulaboh was constructed closer to the ocean
than that in the south of Meulaboh.
Poor compaction and liquefaction might be responsible for thecollapse of embankments adjacent to bridge abutments. If thisoccurs before the arrival of tsunamis, people are unable to use
motorcycles and bicycles for quick evacuation. This indicatesthat it is important for escape routes to be seismically stable.
ACKNOWLEDGEMENTS

This study was supported by a grant from the Ministry of
Education, Culture, Sports, Science and Technology (MEXT) in
Japan. We thank Mr. Mex and his family for sharing their housewith us during the investigation, and all the arrangements made tocomplete our mission.
REFERENCES
Ambraseys, N. N., 1988. Engineering Seismology, Earthquake
Engineering and Structural Dynamics, 17, 1-105.
CTII, 2005. Report on Tsunami Disaster in Banda Aceh (Inception
Report), CTI Engineering International Co., Ltd., Banda Aceh Office (inJapanese).
DLR, 2005. Center for Satellite Based Crisis Information:
Indonesia/Sumatra - Meulaboh - Map Sheet 052011.
Goto, Y., 2005. Preliminary report on the 2005 Sumatra, Indonesia,
earthquake and tsunami disaster, Civil Engineering, JSCE, 90 (5), 31-34.
Honda, R., Takahashi, Y., Pradono, M. H. and Kurniawan, R., 2005.
Estimation of seismic intensity of Banda Aceh in the 2004 Sumatra earth-

41

quake by using questionnaires, Proc. 28th JSCE Earthquake Engineering
Symposium, 216.
Ishii, M., Shearer, P., M., Houston, H. and Vidale, J., E., 2005.
Extent, duration and speed of the 2004 Sumatra-Andaman earthquake
imaged by the Hi-Net array, Nature, 435 (16 June), 933-936.
Iwan, W., D., 2006. Preface to the Special Issue on the Great Sumatra
Earthquakes and Indian Ocean Tsunamis of 26 December 2004 and 28
March 2005, Earthquake Spectra, 22, xi-xii.
Kanamori, H., 2006. Seismological aspects of the December 2004
Great Sumatra-Andaman earthquake, Earthquake Spectra, 22 (S3), S1-S12.
Kawata, Y. as Principal Investigator, 2005. Comprehensive analysisof the damage and its impact on coastal zones by the 2004 Indian Ocean
tsunami disaster, Grant-in-Aid for Special Purposes Research Report,
Ministry of Education, Culture, Sports, Science and Technology (Grant
Number16800055), http://www.tsunami.civil.tohoku.ac.jp/sumatra2004/
report.html.
Matsutomi, H., Sakakiyama, T., Tsuji, Y., Murakami, Y. andNamegaya, Y., 2005. Current speed of the Sumatra tsunami in the residential area of Banda Aceh and Sigli cities, Sumatra Island, Indonesia, Japan
Geoscience Meeting 2005, J113-016.
Saatcioglu, M., Ghobarah, A. and Nistor, I., 2006. Performance ofstructures in Indonesia during the December 2004 Great Sumatra
Earthquake and Indian Ocean Tsunami, Earthquake Spectra, 22 (S3),S295-S319.
Scawthorn, C., Ono, Y., Gamage, N., Ridha, M. and Purwanto, B.,
2005. Lifelines survey - Sri Lanka and Banda Aceh, Report for the Sumatra
Earthquake and Tsunami, Kyoto University, Department of Civil
Engineering.
Sengara, I., Wayan, Puspito, N., Kertapati, E. and Hendarto, 2006.
Survey of geotechnical engineering aspects of the December 2004 Great
Sumatra earthquake and Indian Ocean tsunami and the March 2005 NiasSimeulue earthquake, Earthquake Spectra, 22 (S3), S495-S509.
Tobita, T., Iai, S., Wang, M.-g. and Nakayama, K., 2005. Preliminary
Report of the Mid Niigata Prefecture, Japan, Earthquake in 2004, Journalof Japan Society for Natural Disaster Science, 23 (4), 595-602.
Tsuji, Y., Matsutomi, H., Tanioka, Y., Nishimura, Y., Sakakiyama,T., Kamataki, T., Murakami, Y., Moore, A. and Gelfenbanm, G., 2005.
Distribution of the Tsunami Heights of the 2004 Sumatera Tsunami in
Banda Aceh measured by the Tsunami Survey Team http://www.eri.utokyo.ac.jp/namegaya/suma tera/surveylog/eindex.htm.
Wafid, M. W., 2005. Surface geology of Banda Aceh, Personal communication, Engineering Geology Subdivision, Directorate General of
Geology and Mineral Resources.