Geo-referenced maps for quake damage assessment

Geo-referenced maps for quake damage assessment


Japanese authorities used GeoPDF maps for on-the-ground inspection of property damage in areas affected by earthquake and tsunami, including the Fukushima nuclear evacuation zone

Pre-(left) and post-(right) earthquake images

On March 11, 2011, a 9.0 magnitude earthquake struck northeastern Japan and the ensuing tsunami unleashed waves up to 128 feet high, reaching 6 miles inland. Together, the earthquake and tsunami took more than 15,000 lives, left nearly 8,000 people missing, displaced 450,000 more and damaged properties worth over $300 billion. Adding to the unprecedented scope of these natural disasters was the compromise of the multi-reactor Fukushima Nuclear Plant complex as radiation leaks contaminated the surrounding area.

In such a situation, even as the immediate search and rescue challenges were on, recovery and damage assessment required urgent attention. Federal, prefectural and local governments needed a way to rapidly disseminate, update and share information to determine which buildings and homes were damaged, so that property owners could receive government-issued disaster victim certificates. Owners could then be compensated and reconstruction could begin. Complicating matters was the inability to physically enter the nuclear evacuation zone to conduct on-the-ground inspection of property damage.

Assessing the damage
Because the earthquake so radically altered and submerged the coastline, geospatially referenced maps and imagery were the obvious choice for visualising and exchanging information. In addition, because no one could enter or fly over the evacuation zone near the Fukushima nuclear plant due to radiation exposure issues, satellite imagery was the only way to safely assess damage.

Hitachi Solutions, distributor of TerraGO in Japan and East Asia, proposed that by utilising pre- and post-March 11 maps and satellite imagery combined with property boundary information, damage assessment could be accomplished much more quickly, thus simplifying the clerical work of issuing disaster damage certificates.

The maps would need to cover over 600 square miles land affected by the disaster in Iwate, Miyagi and Fukushima prefectures. Due to the urgency, the maps also needed to be produced rapidly and be easily distributed and updated.

Using TerraGo Publisher and Composer, Hitachi created 38,501 GeoPDF maps and combined them into 42 mapbooks. The GeoPDF maps are comprised of three layers: residential cadastre maps from before the earthquake, post-disaster SAR (Synthetic Aperture Radar) flood estimate data and satellite imagery. The GeoPDF atlas incorporates residential map data from ‘Zmap- TOWN II’ by Zenrin Co, flood estimate data by Pasco Corp and satellite images by DigitalGlobe.

After deciding the specification, the map atlas was produced in two days. Hitachi then donated it to the Japanese Cabinet office which in turn distributed discrete maps from the atlas on DVDs and USBs to the respective prefectural and local governments.

Pre-(left) and post-(right) earthquake images

Quick response
GeoPDF maps enabled users to assess affected areas by comparing the different layers and utilise geographical coordinates when adding information and images to each location. Certification of property damage, which previously required on-site confirmation, was carried out quickly through the comparison of residential maps containing homeowners’ names and post-disaster satellite images.

Hitachi also provided Nikon-Trimble ‘GPS Pathfinder SB’ handheld devices with TerraGo Mobile software to write data on the GeoPDF maps, permitting on-site uploading of current georegistered data and images to the GeoPDF map atlas.

The use of GPS and geographical coordinates in the atlas expedited the inspection process. The GeoPDF maps and satellite images also enabled area-by-area damage assessment for use in planning reconstruction schedules.

By the end of May 2011, approximately 150,000 of the 180,000 applications for disaster victim certificates had been processed. In the Fukushima nuclear evacuation zone, where on-the-ground inspections were not possible, 183 property owners received the Risai Shomeisho disaster victim certificates exclusively on the basis of these GeoPDFs.