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Earth of fire

Actualité volcanique, Article de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
 The Niigata-Yakeyama dome - photo GVP

The Niigata-Yakeyama dome - photo GVP

An increased number of small earthquakes has been detected at Niigata- Yakeyama, located in the island of Honshu in Japan. According to the local observatory, the number of volcanic earthquakes is 4 times larger than usual, with 23 episodes in 24 hours. Low frequency earthquakes, in relation to the fluid internal movements, are dominant.

In addition, increased of fumarolian activity on top of the east side of the volcano and inflation were noticed.

The alert level remains at 1, but accompanied by an exclusion zone of one kilometer radius around the top.

 

Location of the Niigata-Yakeyama in north-central part of the Japanese island of Honshu

Location of the Niigata-Yakeyama in north-central part of the Japanese island of Honshu

Niigata-Yakeyama - fumaroles on the east side of the dome - Doc. NHK

Niigata-Yakeyama - fumaroles on the east side of the dome - Doc. NHK

Niigata-Yakeyama - increased seismicity (the two diagrams above) and slight inflation (bottom) - Doc. Wordpress

Niigata-Yakeyama - increased seismicity (the two diagrams above) and slight inflation (bottom) - Doc. Wordpress

The Niigata-Yaakeyama is a young andésito-dacitic dome above 2,400 meters. Three major eruptions took place in historical times, characterized by pyroclastic flows, surges and lava flows. The current lava dome was built during the 1361 eruption.

The last magmatic eruption dates from 1773; then the activity is summarized in minor phreatic explosions at radial fissures and explosion craters cutting the top and sides of the dome.

Sources :

- Wordpress – Seismic unrest at Niigata-Yakeyama voklcano in Honshu

- Volcanodiscovery et NHK

- Global Volcanism Program – Niigata -Yakeyama

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