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About volcano disaster

Last update date March 14, 2019

There are about 1,500 active volcanoes in the world. 110 active volcanoes are in Japan soon and can say that it is one of the best volcano countries in the world.
Volcano is not in Yokohama-shi, but there are Mount Fuji or Mount Hakone in the outskirts, and damage by volcanic ashes may appear when these volcanoes erupt. When you obtained information such as volcanic warning, forecast, in reference to the next thing, please take action to protect own body.


"Eruption of Sakurajima on August 18, 2013" (the Meteorological Agency offer)


Influence by volcanic ashes

Volcanic ashes write "ash", but it is like small glass piece which magma foams mainly, and is made, and both ingredient and property are different from ash which we burn tree or paper, and there is. As for the damage by ash fall, the following thing is expected.

Influence on body

・Influence on respiratory system including nose and sore throat and a cough
・Itch and pain of eyes
・Pain and inflammation of skin

Influence on everyday life

・Damage to houses by volcanic ashes which included rainwater, and hardened
・Traffic accident with slips and disorder of means of transportation
・Damage to farm products
・Damage to electronic equipment caused by static electricity
・When wet volcanic ashes attach to insulator of the transmission apparatus, it short-circuits, and blackout occurs

Information about volcano

Volcanic warning, forecast

For eruption disaster reduction, we announce volcanic warning, forecast from the Meteorological Agency.
When it is expected by outbreak of volcanism (phenomenon that flying rocks, pyroclastic flow, snowmelt-type mudflow arrive at around crater and residential area from outbreak in a short time, and time postponement until evacuation has few) that volcanic warning occurred with eruption and the expansion that we endanger life, we show "range where caution is necessary" (range endangering life) clearly and announce.

<< about volcanic warning and "range needing caution" >>

From the Meteorological Agency homepage

Volcanic ash fall forecasts

We announce three kinds of volcanic ash fall forecastses (the appointed hour, breaking news, the details) to use of user.
When it erupted, we predict range and ash quantity of ash fall to point from eruption occurrence for six hours and will tell.

<< past ash fall warning (example) >>

From the Meteorological Agency homepage

You can see weather information about other eruption from homepage (the outside site) of the Meteorological Agency.

Action that you should take when it erupted

When volcanoes such as Mount Fuji erupted, volcanic ashes may have ash fall by conditions such as the direction of the wind in Motoichi. Please take the following action to protect the body from volcanic ashes.

  • We wear dust protective mask and will prevent you from breathing in volcanic ashes.

As volcanic ashes are very small, we go with air to the depths of the lungs. Therefore a cough increases and becomes choking. Mucus and sputa increase and may come to have a pain in nose and throat. As person with asthma and bronchitis gets hard by a feeling of clamping, breathing of a cough and chest such as attack, let's be careful. Person with severe disease will be careful about hearts.

  • If volcanic ashes get into eyes, it will prevent you from rubbing by hand. We take off contact lens, and let's use glasses.

When volcanic ashes get into eyes, I feel that we did rumblingly, and itch, pain, hyperemia of eyes are angry. Sticky eye mucus and tears may flow. As it becomes conjunctivitis and stings and it is dazzling and may feel that wound is formed on the surface of eyes in volcanic ashes, let's be careful.

  • In long sleeves, pants, let's protect skin.

Skin may cause inflammation when we touch volcanic ashes. As we come to have a pain, and it is fine, and bacteria may enter at scratch, let's warn


  • Let's be careful about traffic accident.

When volcanic ashes fall, prospect gets worse and becomes hard to show indication of crossing. When volcanic ashes are piled up on road, it becomes slippery, and brakes of bicycle and car become hard to work. We cannot drive when piled up a lot.

  • It will prevent ash from entering building.

We pay jacket, and let's drop ash if we enter building.
When we clean, let's block up gap, air port of door and window with tape and wet towel. It becomes easy to gather when we moisten volcanic ashes with water lightly.

  • Others

We collect right information about volcano on TV radios, and let's confirm.
In Motoichi using disaster prevention information E-mail or tvk (Television Kanagawa), Twitter information of eruption send alerting.
Introduction page of Yokohama-shi disaster prevention information E-mail


Than Cabinet Office brochure

Collection of links
The Meteorological Agency homepage
http://www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/kaisetsu/vol_know.html (the outside site)
Kanagawa "disaster prevention measures of volcano"
http://www.pref.kanagawa.jp/sys/bousai/portal/1,3235,9,13.html (the outside site)

Natl. Res. Inst. for Earth Sci. and Disaster Prevention "bookmark for health hazard local resident of volcanic ashes"
http://dil-opac.bosai.go.jp/publication/pdf/health.pdf (the outside site)

Inquiry to this page

General Affairs Bureau crisis Management Department disaster prevention Planning Division

Telephone: 045-671-4096

Telephone: 045-671-4096

Fax: 045-641-1677

E-Mail address [email protected]

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