Japan's Volcanic Activity

Like earthquakes, Japan is in a prime location on the Ring of Fire to experience many of the world's volcanic activity. As previously noted, Japan is located between four different convergent tectonic plates resulting in general high tectonic activity. Being located on a subduction zone, where one plate dives beneath the other into the asthenosphere, the plate melts and fuels volcanic eruptions. The subduction zone of the Pacific plate diving below the Eurasian plate creates a volcanic arc along the islands of Japan. This image from Earthguide illustrates the relationship between the subduction zone (blue lines with arrows) and Japan's volcanos (white triangles).

With 110 active volcanos in Japan, the Japan Meteorological Agency has created a leveled classification system to illustrate the hazards of the nation's many volcanos. Like earthquakes, Volcanic eruptions cannot necessarily be predicted, however, because they show more visible activity, countries with high activity like Japan are able to invest in understanding risks of volcanos as much as possible and are very adamant on creating safety procedures and warning systems. 



The warning system in Japan is split up into different kinds of warnings: residential areas, non-residential areas, and near-crater warnings. Japan has fine-tuned the classifications of risk into different warning types and has planned how these warnings are communicated to reach all those who are in the volcano's path. From the JMA:
  • There are five Volcanic Alert Levels based on the target area and action to be taken. These are described using action summary keywords.
  • Clear action summary descriptions enable residents to take quick and appropriate action against disasters.
  • Warnings are issued to residential areas when the Volcanic Alert Level is 4 or 5.
  • Near-crater Warnings are issued to areas around the crater when the Volcanic Alert Level is 2, and to non-residential areas near the crater when it is 3.

How warnings are communicated 

Warning classifications, precautions, and explanations
Sources Used:

http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_map_plate_layers_bath.html (Image 1)

https://www.jma.go.jp/en/volcano/ (Image 2 and information)

http://www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/kaisetsu/English/level.html

https://www.cbsnews.com/news/shinmoedake-japanese-volcano-erupts-dozens-flights-grounded/

Comments

  1. Daniel AguayoSeptember 23, 2018 at 4:53 PM

    Good Afternoon Madeleine,
    Excellent post, I had no idea that Japan had such a high number of volcanoes, in the triple digits no less. Its amazing how much careful planning has been put into the warning system for the country to even have what looks like a chain of authority responsible for dispersing the warnings. My county of Haiti has no active volcanoes but I would assume when one does form from the subduction zones near it, they will adopt a mindset for warning disbursement like Japan.

    ReplyDelete

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