How Do You Stay Safe in Izu-Kogen? Tsunamis, Earthquakes and Volcanoes
This guide is for visitors and longer-stay guests in Izu-Kogen and the rest of Ito City. It covers what to do after an earthquake near the sea, how tsunami warnings work and how Ito City sends alerts. It also explains how the city plans to move visitors out if the Izu-Tobu volcanoes become active.
We used pages from Ito City, the Japan Meteorological Agency (JMA), the Japan Tourism Agency's safety site, the Fire and Disaster Management Agency and Shizuoka Prefectural Police. All were read on 2026-10-04. In a real emergency, follow local announcements and staff instructions first.
If the ground shakes while you are near the sea
JMA warns that a tsunami may arrive before a warning is issued if the earthquake is close to the coast. Evacuate if you feel strong shaking, or weak shaking that goes on for a long time.
The Japan Tourism Agency's safety site gives this advice for coasts and riversides:
- A tsunami may come, and it can travel up rivers too.
- When the shaking stops, watch what the people around you do. Go to high ground or a tsunami shelter.
- Tsunami waves are expected to hit again and again. Do not go near the water until the warning is lifted.
- When it is safe, watch for aftershocks and other hazards, then go back to your accommodation.
How JMA tsunami warnings work
JMA issues tsunami warnings and advisories by region, based on the expected tsunami height. It aims to issue them about three minutes after an earthquake. There are three levels:
- Tsunami Advisory: up to 1 m. Get out of the water and leave the coast at once.
- Tsunami Warning: up to 3 m. Evacuate from coasts and riversides at once, to high ground or a tsunami evacuation building.
- Major Tsunami Warning: more than 3 m, given as 5 m, 10 m or over 10 m. Evacuate in the same way, at once.
For very large earthquakes, the first warning may use words instead of numbers. "Huge" is used for a Major Tsunami Warning, and "High" for a Tsunami Warning. JMA updates the warning with heights once it knows the exact size of the earthquake.
Since summer 2020, red and white checked flags have also been used on the coast to show tsunami warnings. They help people who cannot hear well, and swimmers who may not hear over the waves and wind. If you see one, evacuate at once.
What Ito City has put in place for tsunamis
Ito City lists these measures:
- Height signs. Signs showing height above sea level are fixed to 364 utility poles in the city.
- Evacuation buildings. The city has named 38 buildings as tsunami evacuation buildings. The list is a PDF on the city's site.
- Signboards and road markings. Signboards at Orange Beach, Nagisa Park and Fuji-no-Hiroba show the expected flood area, evacuation buildings and wide-area evacuation sites. Markings on roads show the best direction to evacuate.
The governor of Shizuoka designated tsunami hazard zones in Ito on 7 March 2023. They match the city's published tsunami flood estimates. Maps are open to view at the city's Crisis Management Division counter.
The city updated its disaster guidebook in February 2025 and delivered it to every household. New residents can get a copy at the city office and some branch offices.
How alerts reach you in Ito
- Phone alerts. Ito City sends emergency alert messages to mobile phones through NTT Docomo, au and SoftBank. They are free and need no sign-up, though some phones need a setting turned on. People visiting Ito for work or travel also receive them.
- What they cover. The city's list includes tsunami advisories and warnings, eruption warnings, evacuation orders and landslide warnings.
- Outdoor speakers. The city broadcasts from 149 outdoor speakers. Broadcasts include warnings, sirens and evacuation news. A time signal also sounds every day at noon and 17:00.
- Replay by phone. If wind or rain drowns out a broadcast, call 0557-36-2180 to hear it again. The newest message plays first.
- The Safety tips app. Ito City's English page points visitors to Safety tips, a disaster information app for foreign travellers supervised by the Japan Tourism Agency.
Evacuation levels
Since 20 May 2021, Japan has used numbered evacuation levels. Ito City explains them like this:
- Level 3: older people and others who need time should leave dangerous places.
- Level 4: an evacuation order. Everyone in a dangerous place should leave.
- Level 5: a disaster is happening or about to happen. Take action to stay safe at once, for example by moving to an upper floor.
The city stresses that everyone should leave dangerous places by Level 4. If you feel in danger, act even when no order has been issued.
The Izu-Tobu volcano group
JMA describes the Izu-Tobu volcanoes as many small volcanoes in the east of the Izu Peninsula, plus many undersea volcanoes offshore. The largest on land is Mount Omuro, at 580 m.
Earthquake swarms struck the area in 1930. They started again in the late 1970s. In July 1989, during a swarm, the Teishi Knoll off Ito erupted. JMA says it was the first eruption there in recorded history.
JMA watches the volcanoes with seismometers, tiltmeters, GNSS, cameras and other instruments. Volcanic alert levels have applied here since 31 March 2011. On the day we checked, JMA's status was Level 1, which means "be aware this is an active volcano".
Ito City's evacuation plan explains an important difference. No volcano stands where the next vent may open, so there is no crater area to close off first. The level is therefore expected to jump from 1 straight to 4 or 5. JMA uses Level 4 and 5 for warnings to residential areas.
What the volcano plan asks visitors to do
Ito City's wide-area evacuation plan was approved in February 2024. It covers land within 3.5 km of the area where a vent could open, and sea within 3.0 km. Up to 11 districts may need to leave.
JMA would issue a series of bulletins as activity grew. At the stage before Level 4, the city plans to tell visitors to evacuate, which means going home. It does this early so that visitors and residents are not stuck in the same traffic.
- Visitors with a car, including rental cars, leave the affected area by car.
- Visitors without a car leave by train or bus.
- The plan says trains start stopping from Level 4 and stop completely at Level 5. They may stop completely while Level 4 is still in force, for example after an earthquake of intensity 5 lower or stronger.
The plan also gives odds. For every 100 sets of earthquake swarms, it expects about 5 to lead to Level 4 or higher, and about 3 to end in an eruption.
Emergency numbers
- 110: police. Shizuoka Prefectural Police say 110 is the emergency line for incidents and accidents. Give the city name first when you say where you are.
- 119: ambulance. The Fire and Disaster Management Agency's guide says to call 119 when you need an ambulance. Anyone in Japan can use the service.
What we could not verify, and therefore left out
- Which parts of Izu-Kogen lie inside the tsunami hazard zones or the volcano evacuation area. The plan summary lists districts, but we did not check them street by street.
- Expected shaking and tsunami heights in Ito from the Shizuoka Prefecture estimate. The city page links to the prefecture, and we did not read those figures.
- Where tsunami flags are flown in Ito, and in which months.
- Whether the city's phone alerts and speaker broadcasts are in English.
- Whether 110 and 119 calls are answered in English. The official pages we read did not say.
Related guides
- How do you get to Izu-Kogen from Tokyo? Trains, fares and buses from the station
- What is the Jogasaki Coast? The lava coast made by Mount Omuro's eruption
Sources
All URLs retrieved 2026-10-04.
- Tsunami Warning/Advisory and Tsunami Information (Japan Meteorological Agency) — (warning levels, heights, actions, timing, "Huge" and "High"; near-coast quakes)
- Tsunami flags (Japan Meteorological Agency) — (red and white flags since summer 2020)
- Waterfronts (coastal areas, riversides) (Japan Tourism Agency, Safety tips for travelers) — (what to do on the waterfront after an earthquake)
- 伊東市の津波対策について (Ito City) — (height signs; evacuation buildings; signboards; road markings; guidebook)
- 津波災害警戒区域の指定について (Ito City) — (tsunami hazard zones designated 7 March 2023)
- 伊東市総合防災ガイドブック (Ito City) — (guidebook updated February 2025; where to get a copy)
- エリアメール・緊急速報メールの運用について (Ito City) — (phone alerts: carriers, cost, visitors, items covered)
- 同報無線放送について (Ito City) — (149 outdoor speakers; content; daily time signal)
- 同報無線の放送内容を電話で聴けます (Ito City) — (phone replay of broadcasts)
- How to Mitigate Disasters (Ito City) — (Safety tips app for foreign visitors)
- 避難情報について (Ito City) — (evacuation levels 3 to 5)
- 伊豆東部火山群 (Japan Meteorological Agency) — (what the volcano group is; Omuro height; swarms; 1989 eruption; monitoring)
- 火山活動の状況（伊豆東部火山群） (Japan Meteorological Agency) — (current level; alert levels introduced 31 March 2011)
- Volcanic Warnings and Volcanic Alert Levels (Japan Meteorological Agency) — (Level 4 and 5 warnings for residential areas)
- 伊豆東部火山群・伊東市広域避難計画について (Ito City) — (plan approved February 2024; affected range)
- 伊豆東部火山群・伊東市広域避難計画（概要版） (Izu-Tobu Volcano Group Disaster Prevention Council) — (level jump; districts; visitor evacuation timing and means; trains; odds)
- 「110番」を適切に利用するには？ (Shizuoka Prefectural Police) — (what 110 is for; give the city name first)
- Guide for Ambulance Services (Fire and Disaster Management Agency) — (call 119 for an ambulance; anyone in Japan can use it)