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This study evaluates the effects of amount and balance of repair in a gymnasium typical of Japanese schools. Several combinations of main shocks and aftershocks were evaluated. This study showed that a repair using partially retightened anchor bolts is not effective on the short span of the building, but it is effective in the long span, as long as the aftershocks are smaller than 25% of the main shock. The balance of repair does not reduce or amplify the out-of-plane deformation of the walls in the gymnasium, but it causes amplification of the in-plane deformation of the walls in the long span. Therefore, when repair by retightening of anchor bolts is performed, all column bases should be fully retightened as much as possible.
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This study aimed to understand the 20-year recovery process in the Khao Lak area of Phang Nga Province in southern Thailand, which sustained severe damage from the Indian Ocean tsunami caused by the Sumatra earthquake on December 26, 2004, using optical satellite images and results from a total of seven field surveys. This area, where tourism and fishing are the main occupations, was still in the process of recovery when surveyed 10 years after the tsunami. However, in the latest survey 20 years after the tsunami, the resort area was bustling with foreign tourists, and the number of hotels and buildings had increased significantly. Meanwhile, no hard measures such as seawalls were seen in terms of tsunami disaster prevention measures, and instead, progress had been made in installing tsunami warning sirens and evacuation towers, and setting up evacuation routes. Tsunami museums and memorial sites had also been established to pass on the memory of the disaster.
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The 2024 Noto Peninsula Earthquake on January 1, 2024, caused extensive ground damage, including landslides and liquefaction. In Uchinada Town, Ishikawa Prefecture, which is located on the sand dunes, liquefaction caused large ground displacements with sand boils, fissures, subsidence and uplift. Roads, lifelines, buildings and houses were severely damaged. The authors measured the ground displacements by 3D survey using aerial photographs and discussed the effect of surface gradient on the displacements.
