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On March 11, 2011, an Mw 9.0 earthquake shook the Pacific coast of the Tohoku region in Japan. The earthquake triggered a tsunami which maximum wave height reached 40 m at a number of locations. The consequences of the earthquake and those of the tsunami in particular, where devastating. As of August 15, 2001, the National Police Agency of Japan (NPAJ) counted 4,666 missing and 5,717 injured persons. It was necessary for more than 130,000 people to be evacuated. The economic impact of these events has been estimated in at least 140,000 million dollars, which is roughly 2.5% of Japan's GDP.
In terms of structural damage, the NPAJ counted 113,061 total collapses, 145,824 partial collapses, and more than 521,481 structures with partial damage. Records show 284 structures destroyed by fires. Damage locations in roads, railroad, bridges, and infrastructure lifelines added to the hundreds. According to the Ministry of Agriculture and Fishing, the total of damaged fishing boats was above 19,000, and a total of 263 fishing ports were devastated and 63 more recorded partial damage. The former implies that around 37% of the fishing boats of the seven prefectures affected by the tsunami were lost and that 45% of the fishing ports in Japan were inoperable. In terms of damage to the agricultural industry, the area of arable land affected by the tsunami was 23,600 hectares.
This earthquake has caught the attention of the international community not only due to its magnitude and the high seismic intensities observed but also for occurring in a country that is considered one of the best in preparedness to face large seismic events. Nevertheless, devastation in certain regions and the amount of damage recorded were high. Considering the relevance of this event to Mexico, a country with a similar seismic risk, the Institute of Engineering at UNAM (IIUNAM) decide to make a damage reconnaissance trip to the affected regions with the purpose of first-hand gathering of relevant information in addition to that made public via internet on the performance of structures and the Japanese infrastructure during the earthquake as well as on the ongoing recovery process.
Starting on April, 2001, contact was made with Japanese professors and researchers in order to design an itinerary and develop a work plan aimed at obtaining the most information possible during a reconnaissance trip. Eight weekly meetings were held at IIUNAM with the participation of colleagues of both the Department of Structures and Materials and the Department of Seismologic Enginnering. Towards mid June, the details of the trip and its itinerary were defined. Also, the personnel forming the reconnaissance team was selected from the Departments of Structures and Materials, Geotechnics and Seismologic Enginnering. The members of the team were: Gerardo Aguilar Ramos, Jorge Aguirre González, Jorge Arturo Ávila Rodríguez, Eduardo Botero Jaramillo y David Murià Vila.
Main contacts in Japan were Dr. Hitoshi Shiohara from the Architectural Institute of Japan and Dr. Hisahiro Hiraishi (Meiji University). In addition, we had the valuable cooperation and guidance of other professors like Dr. Mitsuyuki Hoshiba and Dr. Tomoaki Ozaki, both from the Japan Metereological Agency, Dr. Masato Motosaka from Tohoku University, and Dr. Shoichi Nakai from Chiba University. Their help was instrumental in meeting the objectives of the trip. Furthermore, meetings with Dr. Takashi Furumura and Dr. Hiroe Miyake both from the Earthquake Research Institute at the University of Tokyo. Towards the end of the trip, Dr. Hisahiro Hiraishi, Chair of the Disaster Committee at the Architectural Institute of Japan invited the Institute of Engineering at UNAM to participate in a seminar on the lessons of the Tohoku earthquake to be hold in March 2012, in Tokyo.
The contacts with our Japanese colleagues were established thanks to the contributions of Dr. Sergio M. Alcocer Martínez de Castro, Dr. Shunsuke Otani and Ing. Juan Manuel Espinosa Aranda. |