Bulletin of the GSI (Vol.64)
Technical trends in the field of surveying and mapping, including satellite positioning and information and communication technologies (ICT), require a new concept to explain the role of the National Geospatial Information Authority (NGIA). In order to facilitate international discussions including bi-lateral technical cooperation and global geospatial information management (GGIM), the concept of Geospatial Infrastructure is formulated.
Geospatial Infrastructure is, in short, what NGIA does to support the Geospatial Society. With further clarification of the subject and the purpose of Geospatial Infrastructure, this concept can be designed to be an instructive concept to guide NGIA.
Takayuki NAKAMURA, Kanichi SAITO and Yoshiyuki MIZUTA
In March 2016, the Geospatial Information Authority of Japan (GSI) established Rules for English Translation of Japanese Geographical Names on maps and Map Expressions for Overseas Visitors as standards to create maps of Japan which are easier to read by foreign visitors. This is in part to help establish the nation as an Advanced Tourism Country, as well as to prepare for the Olympic and Paralympic Games that are to take place in Tokyo in 2020. This article outlines the discussion process, summarizes the standards that were set up, and describes the way to familiarize the public with these standards.
Hiromichi TSUJI, Yuki HATANAKA, Yohei HIYAMA1, Kazunori YAMAGUCHI, Tomoaki FURUYA, Satoshi KAWAMOTO and Yoshihiro FUKUZAKI
The 2016 Kumamoto Earthquake
・Responses of GSI to the 2016 Kumamoto Earthquake
Disaster Management Office, Planning Department
Geospatial Information Authority of Japan (GSI) provides geospatial information to grasp the disaster situation to relevant organizations such as ministries and government offices, local public organizations and the like to help contribute in the lifesaving and rescue activities as well as recovery and reconstruction efforts when a large-scale natural disaster occurs. GSI provided geospatial information to concerned administrative authorities including the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), local government and related organ, in connection with the 2016 Kumamoto earthquake. This paper includes an overview of the disaster and reports on GSI's main responses.
・Detection of Ground Surface Deformation Caused by the 2016 Kumamoto Earthquake by InSAR using ALOS-2 Data
Basara MIYAHARA, Yuji MIURA, Yasuaki KAKIAGE, Haruka UESHIBA, Masaki HONDA, Hiroyuki NAKAI, Tatsuya YAMASHITA,
Yu MORISHITA, Tomokazu KOBAYASHI and Hiroshi YARAI
SAR interferometry (InSAR) analysis of operational L-band SAR satellite of Japan, ALOS-2, reveals a series of coseismic crustal deformations caused by the 2016 Kumamoto Earthquake (April 14-16, 2016). Large coseismic deformation of over 10 centimeters due to the two large foreshocks and over 2 meters due to the mainshock can be clearly identified on the SAR interferograms as well as postseismic deformation up to a few centimeters. These displacements are concentrated around Futagawa-Hinagu fault zone which is a known active fault in Kyushu Island. 2.5-D displacements, more specifically quasi-east-west and quasi-vertical displacements due to the mainshock are also estimated from two interferograms observed from both east and west directions. The estimated displacements are consistent with those of ground GNSS observations. The sequence of the earthquakes causes significant distortion in the geodetic datum of Japan around the focal area, and thus positions of geodetic control points, which are fundamental infrastructure for implementing the datum needed to be revised as soon as possible. The area of the deformation could be promptly identified from the interferograms, and the control points which needed to be revised were quickly determined from the interferograms without any additional ground observation.
・Crustal Deformation Caused by the 2016 Kumamoto Earthquake Revealed by GEONET
Satoshi KAWAMOTO, Yohei HIYAMA, Reiko KAI, Fumio SUGA, Kazunori YAMAGUCHI, Tomoaki FURUYA, Satoshi ABE and Naofumi TAKAMATSU
GNSS observation over the area of the 2016 Kumamoto Earthquake (April 14-16, 2016) reveals coseismic deformations of over 10 centimeters caused by the two large foreshocks and of ~ 1 meter caused by the mainshock as well as a postseismic deformation of up to a few centimeters. Large displacements are concentrated around Futagawa-Hinagu fault zone which is a known active fault in Kyushu Island. Kinematic positioning results imply the two large foreshocks initiated a rupture on the northern part of the Hinagu fault segment, then a rupture neighboring the southern part of the segment. The postseismic deformations that followed seem to be similar to the pattern of coseismic deformation, however, they are widely distributed. The sequence of earthquakes caused significant distortion in the Japanese geodetic datum around the focal area, but GEONET observation enabled a rapid response. Furthermore, it is believed the observation data provided by GEONET will make a significant contribution to understand the fault property along the active fault zone.
・Responses of National Mapping Department to the 2016 Kumamoto Earthquake
National Mapping Department Countermeasures Group
As a result of the 2016 Kumamoto earthquake (hereafter, the Kumamoto earthquake), landslides and ground fissuring occurred over a wide area, and there was major damage to bridges, buildings, and other infrastructure.
The Geospatial Information Authority of Japan (GSI), as a designated government organization under the Disaster Countermeasures Basic Act, Act No. 223 of 1961, “Shall endeavor to collect and disseminate information about disasters.” According to the Basic Disaster Prevention Plan (May 2016) created by the Central Disaster Management Council as well, the GSI “collects information visually and photographically with aircraft” and “works to understand the scale of damage using image information.”
Therefore, the National Mapping Department immediately took and provided aerial photographs in connection with the damage caused by the Kumamoto earthquake using the survey aircraft Kunikaze III, and created and provided photomaps and base maps of emergency restoration measures. This paper reports on those efforts.
・Responses of Geographic Department to the 2016 Kumamoto Earthquake
Geographic Department Disaster Countermeasures Group
The Geographic Department Disaster Countermeasures Group, GSI published landslide distribution maps by interpreting aerial photographs to grasp the extent of damages caused by the 2016 Kumamoto earthquake. The Group also carried out aerial laser surveying in order to assess the ground surface fissures which occurred during the Kumamoto earthquake. This paper reports on such endeavors.
・Field Survey of Non-tectonic Surface Displacements Caused by the 2016 Kumamoto Earthquake Around Aso Valley
Takayuki NAKANO, Tomokazu KOBAYASHI, Kazuki YOSHIDA and Satoshi FUJIWARA
The 2016 Kumamoto earthquake caused a large number of surface ruptures (cracks, depressions) and surface earthquake faults emerged along known active faults. Depressional ruptures occurred in Aso Valley. Remarkable horizontal displacements were observed by satellite SAR analysis around the depressional (graben-like) ruptures area. As a result of field surveys around the area, shortening deformations of constructions were identified along the northern edge of the deformed areas as detected by SAR interferogram as well as opening ruptures around the southern edge of the deformed area. It is presumed that these horizontal displacements with depressional ruptures and shortening deformations were caused by lateral movement of shallow underground layers.
・Responses of Geospatial Information Department to the 2016 Kumamoto Earthquake
Geospatial Information Department Disaster Countermeasures Group
The Geospatial Information Department has provided a variety of geospatial information in connection with the Kumamoto earthquake which occurred in 2016. This report briefly describes the disaster responses.
・Responses of Kyushu Regional Survey Department to the 2016 Kumamoto Earthquake
Kyushu Regional Survey Department
The Kyushu Regional Survey Department, in cooperation with the Main Office of Geospatial Information Authority of Japan (GSI), prepared large-format print-outs of various maps and related materials to help understand the onsite topography and assess the damage situation, immediately after the 2016 Kumamoto earthquake occurred, moreover directly handed over such maps and related materials and explained their content to the persons in charge in affected municipal governments including On-site Headquarters for Major Disaster Management established in Kumamoto Prefectural office.
Also, the Department examined the requests made with respect to surveys and map availability at the time of delivery. As a result, requests were made for “surveys to consider levee repairs” and “status maps of wide area ground displacement to consider resident evacuation in case of flooding”. The Department started work on these right away in cooperation with the Main Office. This paper reports on such responses.