In the past 7 days, this makes FOUR different near (or greater than) 7.0 magnitude earthquakes at this location. Starting with a 6.9M, followed by a 7.2M, followed by a 7.5M, now we see today's (May 7, 2015) large magnitude 7.3 event.
A tsunami warning has been issued for areas within 300km of the earthquake epicenter. Luckily only small waves are being reported.
“Hakone volcano is truncated by two overlapping calderas, the largest of which is 10 x 11 km wide. The calderas were formed as a result of two major explosive eruptions about 180,000 and 49,000-60,000 years ago.
Scenic Lake Ashi lies between the SW caldera wall and a half dozen post-caldera lava domes that were constructed along a SW-NE trend cutting through the center of the calderas.
Dome growth occurred progressively to the south, and the largest and youngest of these, Kami-yama, forms the high point of Hakone.
The calderas are breached to the east by the Haya-kawa canyon. A phreatic explosion about 3000 years ago was followed by collapse of the NW side of Kami-yama, damming the Haya-kawa valley and creating Lake Ashi.
The latest magmatic eruptive activity at Hakone about 2900 years ago produced a pyroclastic flow and a lava dome in the explosion crater, although phreatic eruptions took place as recently as the 12-13th centuries AD.
Seismic swarms have occurred at Hakone during the 20th century. Lake Ashi, along with major thermal areas in the caldera, forms a popular resort area SW of Tokyo.”
“Tokyo, May 4 (Jiji Press)–The Japanese Meteorological Agency said Monday that steam is gushing at the Owakudani volcanic valley in the Hakone hot spring resort area in Kanagawa Prefecture, south of Tokyo.
The agency confirmed that the steam burst had been continuing since Sunday at a hot spring facility at the valley in the town of Hakone in its joint on-site survey with the Hot Springs Research Institute of Kanagawa Prefecture, it said.
On Monday, the town shut down the Owakudani nature trail and part of hiking courses.
While the agency keeps its volcanic alert at the lowest, normal level, it notes that steam may suddenly erupt at Okakudani as slightly increasing volcanic activities are believed to be making hot water unstable in the shallow underground, officials said.
Many volcanic temblors have been measured since April 26 there, according to the officials.“
“TOKYO (AFP) – Japan’s meteorological agency on Tuesday issued a warning to limit access to the popular hot springs resort of Hakone after a nearby volcano became active and began belching steaming gas.
Two minor quakes measuring magnitude 2.0 and 2.4 were recorded Tuesday morning at the volcano, southwest of Tokyo, the agency reported.
“Activity at Hakone… is in a state of uncertainty,” the agency said in an advisory.
“There is a possibility that a minor eruption may suddenly occur,” it said. “Please do not enter dangerous zones.”
The warning, which comes in the middle of the nation’s “Golden Week” spring holidays, was expected to affect tourism there as some 20 million people, including foreign tourists, visit Hakone, one of the most famous hot spring resorts in Japan, every year.
The agency issues restraint advisories when a volcano becomes sufficiently active to spew lava, ash, hot steam and toxic gas as well as rocks and ash.
Japan sits on the Pacific “Ring of Fire”, where earthquakes and volcanic eruptions are relatively commonplace.
Last September, a volcano violently erupted in Mount Ontake, central Japan, leaving 57 people dead and six others still missing in the nation’s deadliest eruption for almost 90 years.”