2019 Yamagata Earthquake
Geology
The northwestern side of Honshu lies on the southeastern margin of the Sea of Japan, an area of oceanic crust created by back-arc spreading from the late Oligocene to middle Miocene. The extensional tectonics associated with the spreading formed a series of N-S trending extensional faults and associated basins. The crust in this area is subjected to east–west compression associated with the convergent boundary between the Amur Plate and the Okhotsk Plate. As a result of this strain, the north–south trending extensional faults are reactivated in a reverse sense. The 1964 Niigata earthquake, the 1983 Sea of Japan earthquake, and the 1993 Hokkaidō earthquake were all a result of similar processes.
Damage and effects
The magnitude 6.4 earthquake triggered a tsunami advisory for three prefectures in Japan. A tsunami with a height of 10 cm was reported in Niigata. The earthquake damaged a total of 149 homes in Akita, Niigata, and Yamagata prefectures.
Casualties
Twenty-six people were reported to be injured, mostly by fallen debris.
Transportation
Sections of the Nihonkai-Tōhoku Expressway and Yamagata Expressway were closed by the East Nippon Expressway Company. National Route 345 was blocked by fallen debris in Murakami.
Utilities
Tohoku Electric Power announced that a blackout occurred in parts of Yamagata and Niigata prefectures because of the earthquake, with 1000 customers impacted in Tsuruoka and 200 customers impacted in Sakata. As a safety precaution, gas services were interrupted in Niigata Prefecture.
Seismic intensity
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/ba/2019-06-18_Tsuruoka%2C_Japan_M6.4_earthquake_shakemap_%28USGS%29.jpg/220px-2019-06-18_Tsuruoka%2C_Japan_M6.4_earthquake_shakemap_%28USGS%29.jpg)
This chart describes the maximum perceived shaking using the Japan Meteorological Agency seismic intensity scale, or Shindo scale, for the earthquake throughout the impacted area.
Intensity | Prefecture | City or municipality name |
---|---|---|
6+ | Niigata | Murakami |
6- | Yamagata | Atsumigawa, Tsuruoka |
5+ | Atsumi, Tsuruoka, Michidamachi, Tsuruoka | |
5- | Niigata | Nagaoka, Kashiwazaki, Aga |
Yamagata | Other areas in Tsuruoka, Sakata, Ōkura, Mikawa | |
Akita | Yurihonjō |