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Very shallow M6.6 earthquake hits Ogasawara region, Japan
A very shallow earthquake registered by the JMA as M6.6 hit Japanese Ogasawara Archipelago at 18:22 UTC (03:22 JST) on August 16, 2018. The USGS is reporting M6.4 at a depth of 11.5 km (7.1 miles) at 18:21 and M6.0 at 18:22 UTC. EMSC is reporting M6.4 and M5.9 at a depth of 10 km (6.2 miles). According to the USGS, the epicenter was located 251 km (156 miles) SE of Iwo Jima, 420.9 km (261.5 miles) SSW of Ogasawara, Japan and 945.4 km (587.5 miles) NNW of Saipan, Northen Mariana Islands. There are no people living within 100 km (62 miles). Although there may be slight sea-level changes in coastal regions, this earthquake has caused no damage to Japan, JMA said. The closest volcanoes are Minami-Hiyoshi and Nikko, both submarine. They have located roughly 100 km (62 miles) W of the epicenter. Periodic water discoloration and water-spouting have been reported over Minami-Hiyoshi since 1975 when detonations and an explosion were als…

Increased activity at Villarrica volcano, alert level raised, Chile

Increased activity at Villarrica volcano, alert level raised, Chile
Chilean authorities have raised the Alert Level for Villarrica volcano to Yellow (the second lowest level on a four-color scale) on December 5, 2017. The last eruptive episode of this volcano started on December 2 (± 7 days), 2014 and ended on October 15, 2017. It had Volcanic Explosivity Index of 1 (on a scale of 7)
OVDAS-SERNAGEOMIN raised the alert level following gradually increasing activity observed at the volcano since November 15, 2017. Increased activity was characterized by volcano-tectonic earthquakes, increased thermal anomalies identified in satellite data, and increased lava-lake activity.
The infrasound network, photos, and field observations confirmed a higher lake level and explosions that were ejecting material deposited in the crater area. Lava fountains 150 m (490 feet) high were documented by POVI during the second half of November.
The public is warned to stay outside of a 1-km radius (0.6 miles) around the crater. 

Geological summary

Glacier-clad Villarrica, one of Chile's most active volcanoes, rises above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andean chain. A 6-km-wide (3.7 miles) caldera formed during the late Pleistocene. A 2-km-wide (1.24 miles) caldera that formed about 3 500 years ago is located at the base of the presently active, dominantly basaltic to the basaltic-andesitic cone at the NW margin of the Pleistocene caldera.
More than 30 scoria cones and fissure vents dot the flanks. Plinian eruptions and pyroclastic flows that have extended up to 20 km (12.4 miles) from the volcano were produced during the Holocene. Lava flows up to 18 km (11.2 miles) long have issued from summit and flank vents. Historical eruptions, documented since 1558, have consisted largely of mild-to-moderate explosive activity with occasional lava effusion. Glaciers cover 40 km2 (15.4 mi2) of the volcano, and lahars have damaged towns on its flanks. (GVP)
Featured image: Near-vertical view into the crater of Villarrica volcano. Credit: Jean-Claude Tanguy, Institute de Physique du Globe de Paris

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