Disasters · Volcanoes & eruptions

What to Do If a Volcano Erupts During Your Japan Trip

If you see an eruption near a volcano or get an eruption bulletin, stop sightseeing and hiking and protect your head and body. Move to a nearby shelter or follow on-site guidance away from the crater. The eruption alert level describes the danger zone and required actions in five stages. Level 1 doesn't guarantee safety. An eruption can start suddenly, before any warning.

Official sources checked: 2026-10-12

If an eruption starts near a volcano

Don't stay to take photos or get closer to the crater. Cover your head with a helmet or backpack, and watch for flying or falling rocks.
Take shelter at a nearby volcanic shelter or mountain hut. If there is none, protect yourself according to conditions — for example, behind a nearby rock.
Follow guidance from managers, police, or firefighters to get away from the crater. If rocks are falling or the way down is dangerous, you may need to take cover nearby first. Whether to descend right away or shelter first depends on conditions on-site.
If you need an ambulance or the fire department urgently, call 119. Say the volcano's name, nearby facilities, and the name on the trail sign so they know where you are.

Official sources: Japan Meteorological Agency · What to do when you get an eruption bulletin (in Japanese) ↗ · Japan Meteorological Agency · What to do when an eruption and volcanic ash hit Mount Mihara (in Japanese) ↗ · JNTO · What to do when a volcano erupts before your eyes (in Korean) ↗ · JNTO · Tourist support hotline and emergency contacts (in English) ↗
Source checked: 2026-10-12

How to read Japanese signs and notices

When you see the Japanese below on signs or phone alerts, check what it means. Don't just look at the number — read what danger it warns of and which area or section it covers.

立入禁止

What it means It means you must not enter this zone.

What to do Don't go past signs or cordon lines. If you're already inside a restricted zone, get out following on-site guidance.

Don't enter restricted areas even if the volcanic alert level is low or others are going in. The photo above is a past example — check on-site guidance for what's currently restricted.

Official sources: Ministry of the Environment, Chubu Regional Office · No-entry sign and cordon bars at Murodo-daira example (in Japanese) ↗
Checked: 2026-10-12

火口周辺規制

What it means It means entry near the volcanic crater is restricted.

What to do Read the restricted range in the notice and don't enter it.

This is wording used at volcanic alert level 2. Restricted distances differ by volcano — don't approach the crater based on the level number alone.

Official sources: Japan Meteorological Agency · Volcanic disaster-prevention terms and cautions (in Japanese) ↗
Checked: 2026-10-12

入山規制

What it means It means entering or hiking in part of the mountain is restricted.

What to do Don't start hiking in a restricted zone. If you're already inside, leave following staff guidance on-site.

This is generally wording used at volcanic alert level 3. Don't linger inside a restricted zone to take photos or sightsee from overlooks.

Official sources: Japan Meteorological Agency · Volcanic disaster-prevention terms and cautions (in Japanese) ↗
Checked: 2026-10-12

噴火速報

What it means A notice that quickly reports that a volcano has erupted.

What to do If you're near the volcano, stop sightseeing or hiking and protect your head and body. Depending on conditions and on-site guidance, enter a nearby shelter or move away from the crater.

This is not a forecast of an eruption. If you see an eruption before an alert, don't wait for the alert.

Official sources: Japan Meteorological Agency · What an eruption bulletin means and what to do (in Japanese) ↗
Checked: 2026-10-12

退避壕

What it means A volcanic shelter where you briefly protect yourself from falling rocks and the like.

What to do If rocks are falling from an eruption and a shelter is nearby and accessible, go in following on-site guidance and protect yourself temporarily.

It's different from a shelter where you stay overnight. It doesn't block every volcanic hazard — confirm on-site whether you can enter now.

Official sources: Japan Meteorological Agency · Handling eruptions, projectiles, and volcanic ash for Mount Mihara visitors (in Japanese) ↗
Checked: 2026-10-12

Red X-shaped bars blocking entry toward Jigokudani on a snowy field, with a no-entry sign — 「立入禁止」 means no entry. Even if you can't read all the Japanese, don't go past X-shaped cordon bars or lines. This is an example of the sign toward Jigokudani at Murodo-daira, Tateyama — a photo from April 12, 2018, so it doesn't show whether the trail is open now or how much snow there is.
Source: Ministry of the Environment, Chubu Regional Office · 「室堂平の利用について」 (About visiting Murodo-daira) · PDL1.0 · used unaltered · Terms of use
Source and terms checked: 2026-10-12

What should I check before visiting a volcano?

Check the warnings for the volcano you're visiting and whether you may enter the crater and trails. Don't set out based on the alert level number alone — also check whether the municipality or facilities have closed off any areas.

The Ministry of the Environment's Mount Aso · 阿蘇山 hiking guidance says not to enter trails closed for earthquakes, heavy rain, or volcanic gas. Follow the entry restrictions of whichever volcano you visit. Trails can be closed for other hazards even with no eruption warning.

Even if a map marks shelters, check separately whether you can use them now. Don't assume that shelters alone protect you from every volcanic hazard.

Find your volcano on the Japan Meteorological Agency site and check each warning's issued time and danger zone. Some volcanoes don't use alert levels — even without a number, read the danger range and action guidance in the warning.
Check municipality, national park, and facility notices for closed trails and overlooks. On-site, don't go past no-entry signs or cordon lines.
Use volcano guidance maps to find nearby shelters and descent routes in advance. Saving the maps you need and your lodging's address on your phone lets you view them even without internet.
When hiking, bring gear the mountain recommends, such as a helmet. If entry is restricted or you can't prepare properly, it's better to drop the crater-area plans.

Official sources: Japan Meteorological Agency · Warnings and activity information by volcano (in Japanese) ↗ · Japan Meteorological Agency · Danger zones and evacuation guidance maps by volcano (in Japanese) ↗ · Japan Meteorological Agency · What eruption warnings and forecasts mean (in Japanese) ↗ · Ministry of the Environment · Where not to go on Mount Aso and hiking preparation (in Japanese) ↗ · Japan Meteorological Agency · What to do when an eruption and volcanic ash hit Mount Mihara (in Japanese) ↗
Source checked: 2026-10-12

Is alert level 1 safe to visit?

No. Level 1 still means it's an active volcano. Ash and other material can shoot from the crater, and there's no guarantee levels rise in order.

The Japan Meteorological Agency announces danger zones and required actions in five eruption alert levels (噴火警戒レベル). Even at the same level, the closed-off range and evacuation methods differ by volcano. Don't apply another volcano's restricted distances or evacuation guidance as-is.

Level 1 · Doesn't mean it's safe

Check the activity information for the volcano you're visiting and follow on-site guidance. Depending on conditions, you may not be allowed inside the crater.

Level 2 · Don't enter the crater area

Look at the danger zones in the warning and the cordon lines on-site, and don't go into the restricted crater area.

Level 3 · Stop hiking in restricted areas

Don't enter zones with hiking bans or entry restrictions. You also must not keep sightseeing or visiting overlooks in restricted areas.

Level 4 · People who need help evacuating move first

In residential areas subject to evacuation, people who need help — such as older adults — evacuate first, and everyone else should prepare to evacuate. As a traveler, follow the municipality guidance where you are.

Level 5 · Leave the evacuation-target area

Leave the danger zone following the municipality's evacuation sites and travel instructions.

An eruption can start suddenly with no clear anomaly observed. If an eruption starts before your eyes, protect your head and body right away instead of waiting for the level to rise or a phone alert.

Learn what the alert levels mean from the Japan Meteorological Agency (in Japanese) ↗

What if an eruption starts before my eyes without a warning?

Don't wait for an alert — protect your head and body. Dodge falling rocks by taking cover at a nearby shelter or descending the mountain. How you escape depends on the danger where you are and on-site guidance.

The Japan Meteorological Agency's eruption bulletin (噴火速報) quickly reports that a volcano has already erupted. It's not an advance forecast. It can be issued even for a volcano with no prior warning.

If you can descend, head down right away; if you must take cover first, use a nearby shelter or mountain hut, or take cover behind a rock. If you haven't entered the mountain yet, stop and stay away from it. Don't run for a distant descent route while rocks are falling.

Large rocks flying from the volcano, and pyroclastic flows — hot ash and gas rushing downhill — can leave almost no time to evacuate once they start. Even with a helmet and shelters nearby, don't enter restricted zones.

Don't restart sightseeing or return to a restricted zone to get your belongings just because smoke from the crater has lessened. Follow municipality and facility guidance on whether it's okay to go back.

Official sources: Japan Meteorological Agency · What to do when you get an eruption bulletin (in Japanese) ↗ · Japan Meteorological Agency · What to do when an eruption and volcanic ash hit Mount Mihara (in Japanese) ↗ · Japan Meteorological Agency · What eruption warnings and forecasts mean (in Japanese) ↗ · JNTO · What to do when a volcano erupts before your eyes (in Korean) ↗ · JNTO · What to do when an eruption warning is issued (in Korean) ↗
Source checked: 2026-10-12

Semicircular concrete volcanic shelter with its entrance open, beside a tree — 「退避壕」 (taihi-gō) is a volcanic shelter for briefly protecting yourself from falling rocks and the like. It's different from an overnight evacuation shelter. This example comes from the Japan Meteorological Agency's Mount Mihara guidance — it doesn't mean other volcanoes have the same facility or that you can enter it now.
Source: Japan Meteorological Agency · 「三原山に登る観光客のみなさまへ」 (To visitors climbing Mount Mihara) · PDL1.0 · used unaltered · Terms of use
Source and terms checked: 2026-10-12

What should I do if volcanic ash falls on the town or my lodging?

Keep windows closed so ash doesn't get indoors. If you must be outside, protect yourself with an ash-blocking dust mask and dust goggles for your eyes. If you're told to evacuate, follow that instruction instead of staying inside.

Breathing in ash can cause coughing or breathing difficulty. If ash gets in your eyes, they may itch, hurt, or redden — don't rub them. Even with a mask and goggles, don't enter restricted craters or areas with volcanic gas.

The Japan Meteorological Agency's ash forecast (降灰予報) tells you where and how much ash will fall. Check the issued time and see whether your area is included and how much is expected. Wind can make the actual fall area and amount differ from the forecast.

If the forecast says 「多量」 (a lot), heavy ashfall is expected. Avoid going out and driving then. If blowing ash is blocking your view, it's better to stop sightseeing or rental-car travel. Wet ash on roads can also be slippery.

Official sources: JNTO · Protecting your airways and eyes from volcanic ash (in Korean) ↗ · Japan Meteorological Agency · What ash forecasts mean (in Japanese) ↗ · Japan Meteorological Agency · What to do by ashfall amount (in Japanese) ↗ · Japan Meteorological Agency · What to do when an eruption and volcanic ash hit Mount Mihara (in Japanese) ↗ · Tokyo Metropolitan Government · Protecting yourself when ash falls and road cautions (in Japanese) ↗
Source checked: 2026-10-12

Can I keep traveling after an eruption?

If you're told to evacuate, stop sightseeing and evacuate first. Then check whether you can stay at your lodging and whether transport to your next destination is running. One volcano's alert level alone can't tell you whether to cancel or continue your whole Japan trip.

Where ash has piled up, rain can send mud and rocks rushing down at once — debris flows. Don't watch only the eruption warning; also check heavy-rain information and the municipality's new evacuation notices.

Before setting out, re-check the latest guidance from your lodging and transport operators. A booking doesn't mean you can enter your lodging now or that trains and buses are running.

Check the municipality's notices for whether your location and lodging are evacuation targets. If your lodging is in an evacuation zone or the road there is closed, don't set out to go back.
From a safe place, call your lodging to ask whether you can stay tonight and whether roads to it are closed. If you can't stay, find a place to stay following the area's evacuation guidance.
Check the airline's website or app to see whether your flight will depart. You also need to check separately whether trains and buses to the airport are running and whether roads are blocked. Even if your flight is scheduled, you may not be able to reach the airport.
If it's unclear whether you can stay at your lodging or reach your next destination, it's better to cut the volcano-area plans first. If you need to change or cancel bookings, ask the operator about their conditions. A disaster doesn't mean every booking is canceled for free.

Official sources: Japan Meteorological Agency · Wording and cautions used in volcanic warnings (in Japanese) ↗ · JNTO · What to do when an eruption warning is issued (in Korean) ↗ · JNTO · Official sites for disaster and transport information (in English) ↗
Source checked: 2026-10-12

Who should I call if I'm hurt or need help?

If you need an ambulance or the fire department urgently, call 119. After evacuating to a safe place, you can call the JNTO tourist support hotline for help with travel difficulties.

When the call connects, say the volcano's name, nearby facilities, and the name on the trail sign. If someone is hurt, describe their condition too. If you can't explain your location or the language isn't working, ask nearby staff to help with the call.

The JNTO tourist support hotline is 050-3816-2787. It's available 24 hours a day in Korean, English, and Chinese. From abroad, call +81-50-3816-2787. If you need an ambulance urgently, call 119 first, before JNTO.

If you can't stay at your lodging, tell shelter staff so. If you need water or medication, or want to ask for an interpreter, say what you need. But there's no guarantee supplies or interpretation will be available right away.

Official sources: JNTO · Tourist support hotline and emergency contacts (in English) ↗
Source checked: 2026-10-12

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Frequently asked questions

Do eruption alert levels always rise from 1 to 5 in order?

Not necessarily. An eruption can start with no clear anomaly observed. Even at level 1, don't enter restricted areas. If you see an eruption, protect your head and body without waiting for an alert.

Official sources: Japan Meteorological Agency · Wording and cautions used in volcanic warnings (in Japanese) ↗ · Japan Meteorological Agency · What to do when you get an eruption bulletin (in Japanese) ↗
Source checked: 2026-10-12

If I get an eruption bulletin, must I always descend right away?

It depends on the situation. If you can descend, head down right away; if rocks are falling and you must take cover first, use a nearby shelter or mountain hut, or take cover behind a rock. Don't just run for a distant descent route — move away from the crater following on-site guidance.

Should I close windows even with light ashfall?

Yes. The Japan Meteorological Agency says to close windows even with light ashfall. Outside, protect yourself with a dust mask and dust goggles, and don't rub your eyes if ash gets in. If you're told to evacuate, evacuating comes before staying inside with windows closed.

Official sources: Japan Meteorological Agency · What to do by ashfall amount (in Japanese) ↗ · JNTO · Protecting your airways and eyes from volcanic ash (in Korean) ↗ · Japan Meteorological Agency · What to do when an eruption and volcanic ash hit Mount Mihara (in Japanese) ↗ · JNTO · What to do when an eruption warning is issued (in Korean) ↗
Source checked: 2026-10-12

If the eruption calms down, can I go back to a restricted overlook?

Don't enter a restricted zone just because smoke from the crater has lessened. Check whether the municipality or facility says it's okay to return. Even at the same level, the restricted range differs by volcano — don't apply another mountain's guidance as-is.

Official sources: Japan Meteorological Agency · Wording and cautions used in volcanic warnings (in Japanese) ↗ · Japan Meteorological Agency · What eruption warnings and forecasts mean (in Japanese) ↗ · Ministry of the Environment · Where not to go on Mount Aso and hiking preparation (in Japanese) ↗
Source checked: 2026-10-12

When the eruption warning is lifted, are other dangers over too?

No. Where ash has piled up, rain can send mud and rocks flowing down as debris flows — dangers an eruption warning alone won't tell you about. Check heavy-rain information and local evacuation notices together, and don't enter on-site restricted areas.

Official sources: Japan Meteorological Agency · Wording and cautions used in volcanic warnings (in Japanese) ↗ · JNTO · What to do when an eruption warning is issued (in Korean) ↗
Source checked: 2026-10-12

Can I ask JNTO for help while traveling in Japan?

The JNTO tourist support hotline at 050-3816-2787 takes inquiries in Korean, English, and Chinese 24 hours a day. If you need an ambulance or the fire department urgently, call 119 first. Calling JNTO doesn't guarantee rescue or immediate supplies or interpretation at a shelter.

Official sources: JNTO · Tourist support hotline and emergency contacts (in English) ↗
Source checked: 2026-10-12

Official sources for this guide

Check local notices for current warnings and entry restrictions. For trains and flights, check the transport operators' latest notices.