oklahoma-earthquake

Oklahoma earthquake: M=5.6 quake shakes seven states

At 5:02 Saturday morning, a Magnitude 5.6 earthquake struck 14km NW of Pawnee, Oklahoma. This was a fairly shallow quake occurring about 6.59 km below Earth’s surface, and it caused strong shaking.

Based on early reports, the USGS estimates that there will be no casualties or major damage. However, some injuries or economic losses may still be possible.

熊本地震: M6地震がM7地震を誘発し,その後周辺の活断層にも影響が

熊本での地震続発を報告してから4ヵ月が経過しました.本年4月14日に発生した最初のM6.5地震から28時間後の16日には,同じ断層帯でM7.3地震が発生しました.この地震で,熊本市,益城町,西原村,南阿蘇村など,日奈久断層帯,布田川断層帯に沿った地域で甚大な被害がもたらされました.以下では,これまで得られたいくつかの知見を紹介します.

Damage map of the Italy earthquake in Amatrice.

Italy earthquake: NASA radar maps reveal massive damage

Last week’s M=6.2 Italy earthquake left many parts of the medieval city of Amatrice in ruin. In the old part of the city, most buildings were made of unreinforced masonry, leaving them susceptible to collapse [Guidoboni and Valensise, 2015]. Amatrice was all but destroyed in three large shocks over 19 days in 1703, and so the part of the town that was highly damaged on 24 August 2016 was composed of buildings largely constructed about 300 years ago. In contrast, the newer construction in the east side of the town came through the M=6.2 quake relatively unscathed.

Living with Liquefaction

During intense earthquake shaking, water-saturated sediments can turn into a slurry (liquefaction), causing buildings, cars and other heavy objects lying on top of what were formerly stiff, dry sediments or …