Japanese scientists worry March 9.0 earthquake may unleash volcanic nightmare

July 28, 2011TOKYO – It is not unusual for dormant volcanoes to erupt several months or years after a great earthquake. But is there a causal relationship between massive earthquakes and volcanic eruptions? Will the Great East Japan Earthquake affect volcanoes in this country? Researchers have been trying to answer these questions. Two days after a magnitude-9.5 earthquake struck Chile in 1960, the Puyehue volcano in southern Chile erupted. The volcano erupted again in June this year, following a magnitude-8.8 temblor in February last year. It is difficult to establish a statistical correlation between massive earthquakes and volcanic eruptions given the low frequency of such events. But research conducted by Masaaki Churei, a former chief of volcanology of the Meteorological Agency, shows a historical correlation between the two phenomena. “Volcanic eruptions in the Tohoku region spiked before and after great earthquakes off the Sanriku coast in the region,” Churei said. According to a research paper by Churei published in 2002, 13 volcanic eruptions, including those of Mt. Chokai and Mt. Azuma, occurred in six prefectures of the Tohoku region over a period of 156 years from 1841 to 1996. During that period, four magnitude-8-class earthquakes–including the Meiji Sanriku Earthquake of 1896 and the Ansei Hachinohe Earthquake of 1856–occurred in the Japan Trench. Of the 13 eruptions, 12 occurred within eight years before or after the massive earthquakes, Churei’s research found. It also showed that volcanoes became active three or four years after the major earthquakes. Churei found similar phenomena in the Hyuganada sea off eastern Miyazaki Prefecture. Toshitsugu Fujii, professor emeritus at the University of Tokyo and chairman of the Coordinating Committee for the Prediction of Volcanic Eruptions, said, “If accurate statistical data could be compiled based on exact eruption records, correlations between volcanic eruptions and earthquakes could be seen in various parts of the world.”
A link between volcanoes and massive earthquakes can be found under the sea. In the sea off the eastern coast of the Tohoku region, for example, the Pacific tectonic plate moves westward and subducts beneath the North American continental plate to create the Japan Trench, which extends from north to south. The westward-moving plate contains much moisture and transfers some of it to the continental plate during subduction. In the presence of moisture, it is believed that rocks at a certain depth tend to turn into magma when subject to high temperature and high pressure. Indeed, just above where this magma is generated is a “volcanic front” along a north-south axis in the Tohoku region in parallel with the Japan Trench. A major earthquake occurs when the edge of an oceanic plate suddenly slides under a continental plate. The positional and dynamic relations of the two plates change, possibly affecting magma formation. Thus, earthquakes and volcanoes essentially are closely linked. But it is estimated to take from several thousand years to tens of thousands of years for magma created deep in a plate to rise to the Earth’s surface. Therefore, a different mechanism seems to be at work when a massive earthquake affects volcanic activities shortly after its occurrence. In the aftermath of the March 11 earthquake, underground volcanic activity spiked at 20 volcanoes throughout the country, including below Mt. Yakedake straddling Nagano and Gifu prefectures, Mt. Hakone on the border of Kanagawa and Shizuoka prefectures and Mt. Aso in Kumamoto Prefecture. Earthquakes that can be sensed by humans also occurred. Commenting on the cause of this phenomenon, the Meteorological Agency said: “Magma chambers below the volcanoes were shaken by seismic waves, causing gases in magma to create magma bubbles. This resulted in earthquake swarms.” Many volcanologists are focusing on the hypothesis that crustal movements triggered by earthquakes squeeze out magma to cause volcanic eruptions. One such scientist is Eisuke Fujita, a senior researcher of the National Research Institute for Earth Science and Disaster Prevention. He has researched how the gravitational pressure from rocks around the magma chamber of Mt. Fuji changed in the aftermath of the March 11 earthquake compared with that before the disaster. –Yomiuri.jp
This entry was posted in Earth Changes, Earth Watch, High-risk potential hazard zone, Potential Earthchange hotspot, Seismic tremors, Volcano Watch. Bookmark the permalink.

11 Responses to Japanese scientists worry March 9.0 earthquake may unleash volcanic nightmare

  1. Marshallrn says:

    For not being to sure of the connections between earthquakes and volcanoes, they sure seem to know exactly what causes these swarms. “magma bubble” really!?! More like bubbling magma to the surface. I find it hard to believe that our planet is the same as it’s been for the past two hundred years. Things are deffenetly changing in the geological world and I will see more amazing things I’m the rest of my life time. So why any question what is or is not happening. Just prepare and enjoy the ride!
    Stay safe Peoples


  2. Stephen says:

    Hi Alvin,

    How can strong tremors awake dormant volcanoes?


    • Earthquake corrode fault and fissure intergrity and basically you disturbed something pressurized…you’ve got problems. Earthquakes have secondary effect product by seismic waves and they propagate in the planetary medium.


  3. luisport says:

    A couple of days ago I book marked a couple of spanish forums, just to keep up to things.

    Now they are saying the other islands are showing instability especially La Palma.

    I’m no expert. What do you think about his:


    • luisport says:

      Earthquake activity below El Hierro volcano, Canary Islands, Spain
      Last update: July 28, 2011 at 12:47 pm by By Tom Pering Leave a Comment

      Recently El Hierro volcano of the Canary Islands has been experiencing a seismic swarm beneath it, which as of yesterday reached to over 700 events.

      Most of these events have been at Magnitudes of around 2 (+/-0.5) and are clustered beneath El Hierro whilst the depths of these earthquakes have been roughly between 9 and 16 km for the most part, with the exception of a few shallower and deeper quakes, the shallowest of which has been 4 km.
      If we look at these earthquakes in two plots here http://www.volcano-blog.com/hierro.html we can see the clustering of these earthquakes is mainly confined to an oval area at 10 km depth.

      El Hierro is a broadly basaltic volcano which might have been active in 1793 although this is uncertain.

      So the big question is, what’s happening here?
      It is possible that there is magma on the move at depth, perhaps moving into a magma chamber.
      Does this mean that there will be an eruption? Maybe, maybe not.
      The majority of magma intrusions do not reach the surface, and as has been seen elsewhere, in the past, activity can cease at anytime.

      As of yet (to my knowledge) there have been no other signs of moving magma at the surface such as ground deformation or increased gas emission, although GPS antenna have been set up by officials at the Canary Islands.
      For now it is too early to tell what (if anything) will happen, so keep watching.
      If you would like to follow these earthquakes in more detail or look at the raw data, visit here .

      El Hierro Volcano Information :
      The triangular island of Hierro is the SW-most and least studied of the Canary Islands. The massive Hierro shield volcano is truncated by a large NW-facing escarpment formed as a result of gravitational collapse of El Golfo volcano about 130,000 years ago. The steep-sided 1500-m-high scarp towers above a low lava platform bordering 12-km-wide El Golfo Bay, and three other large submarine landslide deposits occur to the SW and SE. Three prominent rifts oriented NW, NE, and south at 120 degree angles form prominent topographic ridges. The subaerial portion of the volcano consists of flat-lying Quaternary basaltic and trachybasaltic lava flows and tuffs capped by numerous young cinder cones and lava flows. Holocene cones and flows are found both on the outer flanks and in the El Golfo depression. Hierro contains the greatest concentration of young vents in the Canary Islands. Uncertainty surrounds the report of an historical eruption in 1793.

      El Hierro Information courtesy volcano.si.edu (Smithsonian Institution)



  4. Bone Idle says:

    Mt Fuji erupted in 1707 several weeks after an estimated Mag 8.6 (Hoei earthquake).
    Largish eruption. Same size eruption now would be very dispruptive.


  5. luisport says:

    28.07.2011 | 11:30

    Glacial Outburst Flood in Skaftá River
    A glacial outburst flood has commenced in Skaftá river in South Iceland; Skaftárjökull, a valley glacier off Vatnajökull glacier east of Langisjór, a higland lake at Vatnajökull’s southwestern borders, is the source of the outburst.

    Skaftá river.

    The police urge travelers to stay clear off the river source or near shallow banks due to the traces of sulfur in the river; sulfur can damage the mucous membrane in the eyes and respiratory tract. Experts are keeping an eye on further progress of the glacial outburst, ruv.is reported about an hour ago.

    The Civil Protection Department warns traveler that Skaftártunguvegur road may go under by Hvammur area and the road in Skaftárdalur may become closed to traffic. During the previous glacial outburst the road in the Hólaskjól area in Thórsmörk in the northern parts of the Fjallabaksleid were flooded.

    The last glacier outburst flood occurred last summer.


  6. luisport says:

    Ongoing Activity: | Karymsky, Eastern Kamchatka (Russia) | Kilauea, Hawaii (USA) | Kizimen, Eastern Kamchatka (Russia) | Puyehue-Cordón Caulle, Central Chile | Sakura-jima, Kyushu | Shiveluch, Central Kamchatka (Russia)


  7. luisport says:

    Formation of the Aira Caldera, Southern Kyushu, ∼22,000 Years Ago

    Shigeo Aramaki

    Earthquake Research Institute, University of Tokyo

    About 22,000 years ago a series of large-scale pyroclastic eruptions produced the Aira caldera 20 km × 20 km wide at the northern end of Kagoshima Bay in southern Kyushu. It started with a Plinian pumice eruption (Osumi pumice fall, 98 km3) followed by oxidized, fine-grained Tsumaya pyroclastic flow (13 km3), both erupted from a vent located at the present site of SAKURAJIMA volcano, 8 km south of the caldera center. After a very short pause, violent explosive ejection of the basement rock fragments and pumiceous materials occurred at the central vent, gradually changing itself to a huge eruption column rapidly collapsing to form the Ito pyroclastic flow about 300 km3 in volume. The earliest phase produced up to 30-m-thick Kamewarizaka breccia developed along the caldera rim and charged with basement (lithic) fragments up to 2 m across. The breccia is a near-vent variety of the bottom concentration zone of lithics in the Ito deposit. Various textural features and monotonous petrologic character indicate that the main part of the Ito pyroclastic flow was emplaced by a simple, short-lived eruptive mechanism. The Aira-Tn ash, a fine-grained counterpart of the Ito pyroclastic flow, covered a wide area more than 1000 km from the vent. Evacuation of more than 110 km3 of rhyolitic magma produced a funnel-shaped collapse structure with the center of the magma chamber about 10 km deep. Like many other Japanese Quaternary calderas, the Aira caldera is considered to heave formed not by a piston cylinder-type subsidence utilizing a ring fracture but by coring and high-angle slumping of the wall rocks into a funnel-shaped central vent. The outline of the caldera was strongly controlled by the faults bounding the volcano-tectonic graben forming Kagoshima Bay.


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