Development of Spatial Information Database ofBuilding Damage and Tsunami Inundation Areas
following the 2010 Chile Earthquake
Fumio YAMAZAKI1, Yoshihisa MARUYAMA2, Hiroyuki MIURA3, Shizuko
MATSUZAKI4 and Miguel ESTRADA5
1Professor, Dept. of Urban Environment Systems, Chiba University(1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan)
E-mail:yamazaki@tu.chiba-u.ac.jp
2Associate Professor, Dept. of Urban Environment Systems, Chiba University(1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan)
E-mail:ymaruyam@ tu.chiba-u.ac.jp
3Assistent Professor, Dept. of Built Environment, Tokyo Instisute of Technology(4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan)
E-mail: hmiura@enveng.titech.ac.jp
4Graduate Student, Dept. of Urban Environment Systems, Chiba University(1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan)
E-mail: 10td0309@graduate.chiba-u.jp
5Associate Professor, Japan-Peru Center for Earthquake Engineering and Disaster Mitigation, National University ofEngineering, Peru (Av. Túpac Amaru 1150, Lima 25, Peru)
E-mail: estrada@uni.edu.pe

This paper presents the results of a field survey conducted by the authors after the 2010 Chile earthquake.
The authors visited the affected area about a month after the earthquake. The GIS datasets for the damagelevels of buildings in Talca and the tsunami-inundated areas in Talcahuano, Dichato, and Constitución are
constructed in this study, and a series of fundamental analyses are performed using a digital elevation
model (DEM). Further, the usefulness of satellite images captured after the earthquake to detect damagedbuildings in Talca is discussed using the GIS datasets constructed in this study.
Key Words : 2010 Chile earthquake, GIS, building damage, tsunami-inundated area, digital elevation
model (DEM)

1. INTRODUCTION
The 2010 Chile earthquake occurred off the coast of the Maule Region of Chile on February 27, 2010, at
03:34 local time (06:34 UTC) with a magnitude of 8.8 on the moment magnitude scale. The epicenter was
offshore from the Maule Region, approximately 335 km southwest of Santiago, the capital of Chile, and 105
km north-northeast of Chile’s second largest city, Concepción. It is reported that a severe ground motion withthe Modified Mercalli Intensity (MMI) scale of VII was felt widely in Chile and that the extensive damage wascaused by the ground shaking and tsunami1). The total economic loss estimates range from USD 15 to 30
billion, which correspond to 10% to 15% of Chile’s real GDP2). According to the report on the scene, the actual
death toll was 486 as of March 8, 2010, and approximately 370,000 homes were damaged2).
The authors visited the affected area about a month after the event as part of an international research project“Enhancement of earthquake and tsunami disaster mitigation technology in Peru”3), which is under the research program “Science and Technology Research Partnership for Sustainable Development (SATREPS)”4)
supported by the Japan Science and Technology Agency (JST) and the Japan International Cooperation
Agency (JICA). The lessons learned from the 2010 Chile earthquake are expected to apply to the earthquake
disaster mitigation technologies in Peru because the two countries have common regional tectonics and socialsurroundings.
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Fig. 1 Locations of cities visited by the authors and outline of field survey by the authors.

Fig. 2 Survey route and field photos in Santiago—April 2, 2010

Three teams of Japanese and Peruvian researchers were dispatched by the SATREPS project to carry out
field surveys. In this paper, the results of the field survey performed by Damage Assessment Group and Disaster Mitigation Plan Group are presented. The spatial damage data, topographical maps, and satellite images
provided by different institutions are compiled by the geographical information system (GIS), and the primitive analyses are conducted to reveal the characteristics of the tsunami-inundated areas in view of elevations
and damage incidents to adobe and unreinforced masonry buildings, which are also widely seen in Peru.

2. OUTLINE OF FIELD SURVEY
The authors arrived in Santiago on April 2, 2010. We drove to Concepcíon the next day and visited thetsunami-affected areas of Talcahuano, Dichato, and Constitución. We moved to Talca on April 7 and left
Santiago on April 8. Before leaving, we visited Valparaíso and Viña del Mar. Figure 1 shows the locations ofthe cities that we visited during the survey.
Figure 2 shows the route of our field survey in Santiago and some field photographs. The route was recorded by a portable GPS device during the survey and the location of the photo shooting could be identified as
the location data were embedded in the Exchangeable Image File Format (EXIF). An RC building with 20stories constructed in 2003 suffered from shear failures in columns and walls at the first and the second stories.
A collapsed highway bridge and an RC building with the collapsed first floor were found. The locations ofthese sites are also shown in the survey route in Fig. 2.
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Fig. 3 Survey route and field photos in Concepcíon—April 4, 2010

Fig. 4 Survey route and field photos in Dichato—April 5, 2010

Figure 3 shows the survey route in Concepcíon. An RC building with the damaged middle floor was foundat the site numbered 1. An RC building with 15 stories had collapsed completely at the site numbered 2. Theroad bridges collapsed at sites 3 and 4. The temporary bridge girder was constructed two days after theearthquake at site 3. Although the photos are not shown in this paper, the adobe and unreinforced masonry
constructions were severely damaged in the urban area.
Figure 4 shows the survey route in Dichato. It is reported that more than 80% of the built-up area in Dichato
suffered from tsunami5). As shown in the field photos, the buildings collapsed because of the tsunami waves. Aship was conveyed against the river flow because of the tsunami and eventually found at site 3.

3. CONSTRUCTION OF GIS FOR BUILDING DAMAGE AND TSUNAMI-INUNDATED
AREA(1) Building damage GIS in Talca
Talca is the capital of both Talca Province and Maule Region. Its population is approximately 200,000, and
it is approximately 250 km south of Santiago and 60 km northwest of the epicenter of the 2010 Chile Earthquake5). According to USGS1), Talca was affected with a severe ground motion with the MMI scale of VII.
During our survey, we interviewed officials from Maule Regional Office to investigate the damage ofbuildings. As a result of our interview, an image file that shows the damage levels of buildings was provided.
The polygons, which indicate the building lots, are classified into four levels, namely, to be removed, to berepaired, no damage, and under investigation. It should be noted that the image file was compiled with thedamage dataset as of March 31, 2010.
In this study, the location of the image file was established in terms of map projections. The satellite imageand road data presented in Google Earth were employed as a base map to georeference the image file. Then, the43Fig. 5 GIS file to show the damage levels of buildings in Talca and locations of field photos

Fig. 6 Cumulative frequencies of the areas of building lots with respect to the damage level

Fig. 7 Comparison between pre- and post-event satellite images to detect affected buildings

image file was converted to a GIS file with polygons to identify the damage levels of buildings. Figure 5
shows the developed GIS file presented by Google Earth and some field photos to show the examples ofdamaged buildings.
In all, 5617 polygons were projected to the map coordinate system. 1559 (27.8%), 1872 (33.3%), and 1864
(33.2%) buildings were classified as to be removed, to be repaired, and no damage, respectively. The typicalconstruction types in Talca are adobe and unreinforced masonry buildings, which are primarily used for older
constructions with 2–4 stories (dating back to before the 1960s–70s). Modern buildings that were designed
according to the current codes suffered minor, repairable damage, while a large number of adobe and unreinforced masonry constructions suffered significant damage6).
Figure 6 shows the cumulative frequencies of the areas of building lots with respect to the damage level.
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Fig. 8 Tsunami-inundated areas in Talcahuano, Dichato, and Constitución

The mean of all the georeferenced areas was approximately 430 m2 and was almost equal to that of the areas
associated with the buildings to be repaired. The mean of the lot areas of the buildings to be non-damaged wasapproximately 340 m2, which was considerably smaller than that of the buildings to be removed. On the basisof the results, it has been speculated that the newer buildings are constructed in relatively small lots; however,the construction periods are not available at this moment.
Recent advancements in remote sensing technologies and their applications have made it possible to use
remotely sensed imagery for estimating the damage distribution due to natural disasters. Among them,high-resolution optical satellite imagery, which has become available in the last decade, has made satellite
remote sensing more useful in disaster management since even the damage status of individual buildings can beidentified7), 8). Figure 7 compares the pre- and post-event high-resolution optical satellite images with the GIS
dataset shown in Fig. 5. As for the pre- and post-event images, the image captured by QuickBird9) on January
1, 2008, which is presented in Google Earth, and that captured by WorldView-210) on March 10, 2010, areemployed in this study. A comparison of the pre- and post-event images revealed that some of the affectedbuildings could be visually detected, but not all the damaged ones could be identified appropriately. Since thepost-event image was captured with the large off-Nadia angle (40.3°), the quality of image is not sufficient forvisual damage inspection. Moreover, the number of affected buildings whose roofs had completely collapsed issmall in Talca. Hence, it can be concluded that the damaged buildings in Talca are difficult to be detected
through visual damage inspection using satellite images.
(2) Development of GIS for tsunami-inundated area
Various institutions released the maps to show the damage distribution at their Web sites after the 2010 Chileearthquake. The tsunami-inundated areas interpreted from satellite and aerial images were published by National Office of Emergency of the Interior Ministry (ONEMI) of Chile11). On the basis of the maps, the numberof affected buildings and that of causalities were estimated.
In this study, the tsunami-inundated areas were projected onto a map coordinate system, and the topographical conditions were evaluated in terms of the elevation. The inundated areas in Talcahuano, Dichato, andConstitución were converted to the GIS data and compared with the digital elevation model (DEM). The DEM
employed in this study is the ASTER Global Digital Elevation Model (GDEM) developed by the Ministry ofEconomy, Trade, and Industry (METI) of Japan and the United States National Aeronautics and Space Administration (NASA)12). The ASTER GDEM is a highly accurate DEM covering all the land on earth with the45

Fig. 9 Elevations along the transverse lines set in Fig. 8Fig. 10 Measurement of tsunami inundation depth in Talcahuano

spatial resolution of 30 m.
Figure 8 shows the tsunami-inundated areas in Talcahuano, Dichato, and Constitución and the distributionsof the elevation derived from the ASTER GDEM. The elevations in the inundated areas are lower than 20 m on
the whole except for a certain area in Constitución. As shown in the figure, we set the two traverse lines in each
inundated area. The elevations were extracted along the two lines. The extracted elevations are illustrated interms of the distance from the coastline in Fig. 9. As for Line 2 in Constitución, the elevations are presentedwith respect to the distance from the Maule River. The relatively low elevations and slow grades result in long
travel distances of the tsunami wave. According to Line 2 in Talcahuano, the tsunami wave could travel approximately 2000 m from the coastline. Line 1 in Constitución was assigned to identify the surveyed site by
Imamura et al.13). According to their report, the tsunami runup height was 28.3 m at the site. Since the DEM
used in this study is a global dataset that consists of 30-m grid cells, the elevation at the site is estimated to beapproximately 23 m. The slope is estimated to be approximately 67% and is almost equivalent to that reported
by Imamura et al., which is 63.5%13).
As shown in Fig. 10, the inundation depth was measured at several sites in the three cities. The inundation
depth along the beachfront street in Talcahuano was larger than 150 cm, but a depth of 55 cm was observed inits bystreet (site 4). Figure 11 summarizes the measurements in the three cities. The inundation depth is presented with respect to the elevation and the distance from the coastline. As for the results in Constitución, therecords are shown with respect to the distance from the Maule River. A clear tendency is not seen in the rela46

Fig. 11 Summary of the measurement of tsunami inundation depth

tionship between the tsunami inundation depth and the elevation. The recorded depth in Talcahuano andConstitución decreased with an increase in the distance from the coastline or the river; however, this tendency
is not seen from the records in Dichato because of the insufficient number of measurements.

4. CONCLUSIONSIn this paper, the results of a field survey conducted after the 2010 Chile earthquake by the authors duringApril 2–8, 2010, are presented. The GIS dataset for the building damage in Talca was developed by establishing the location of the image file in terms of map projections. The usefulness of high-resolution satellite
images to detect the building damage in Talca was investigated with the aid of the constructed GIS dataset.
Moreover, the tsunami inundation maps published by ONEMI were georeferenced, and the characteristics of
the inundated areas were evaluated in view of the elevation.
According to the relationship between the building damage levels and the lot areas, the mean of the areas
associated with the non-damaged buildings was the smallest, while the mean of the areas associated with thebuildings to be removed was the largest. In Talca, modern buildings that were designed according to the current codes suffered minor, repairable damage, while a large number of adobe and unreinforced masonry constructions, which were built in the 1960s–70s, suffered significant damage. On the basis of these circumstances, it has been speculated that the newer buildings may be constructed in relatively small lots; however, theconstruction periods are not available at this moment. According to the results of a visual damage inspection
using pre- and post-event satellite images, it was concluded that the damaged buildings in Talca could not beappropriately detected because of their damage patterns and the quality of the post-event satellite image.
A comparison of the georeferenced tsunami-inundated areas with the elevations obtained from the ASTER
GDEM revealed that the elevations in the inundated areas were lower than 20 m on the whole except for acertain area. A clear tendency was not seen in the relationship between the tsunami inundation depth and theelevation. The recorded inundation depth in Talcahuano and Constitución decreased with an increase in thedistance from the coastline or the river.
These findings of our field survey after the 2010 Chile earthquake will be expanded in the earthquake andtsunami disaster mitigation technology in Peru through the SATREPS project.

ACKNOWLEDGMENT: The authors would like to express their sincere gratitude to the Japan Science andTechnology Agency (JST) for the financial support in conducting the field survey under the SATREPS project“Enhancement of earthquake and tsunami disaster mitigation technology in Peru” (Principal Investigator: Prof.
Fumio Yamazaki, Chiba University).

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