1995 Neftegorsk earthquake


The 1995 Neftegorsk earthquake occurred on 28 May at on northern Sakhalin Island in the Russian Far East. It was the most destructive earthquake known within the current territory of Russia, with a magnitude of and maximum Mercalli intensity of IX that devastated the oil town of Neftegorsk, where 2,040 of its 3,977 citizens were killed, and another 750 injured.
90% of the victims were killed by the collapse of 17 five-story residential buildings. While Western media generally attributed the collapses to allegedly poor construction and shoddy materials of Soviet-era construction, a geotechnical study faulted a failure to accommodate the possibility of soil liquefaction in an area that was considered "practically aseismic".
The Belgian Centre for Research on the Epidemiology of Disasters' EM-DAT database places the total damage at $64.1 million, while the United States' National Geophysical Data Center assesses the damage at $300 million.
This quake was not only catastrophic, it was totally unexpected: earthquakes with magnitudes greater than 6 were not known to occur in the area of northern Sakhalin Island. It is also of great scientific interest because it occurred near a poorly known tectonic plate boundary where the Okhotsk Plate is crashing into the Amurian Plate, and indicates that the plate boundary is associated with a north-south striking seismic belt that runs the length of Sakhalin. More precisely, this earthquake occurred on the Upper Piltoun fault, which branches off the main Sakhalin-Hokkaido fault that runs along the east side of the island.
of surface rupturing was observed, with an estimated average lateral displacement of about 4 meters, but up to in some places. The unusual strength of this quake and length of rupturing, and the low level of seismic activity beforehand, has been attributed to the accumulation of strain over a long period of time on a locked fault segment.