Sources, Warnings & Safety
Tsunami Information
A tsunami is a series of ocean waves usually triggered by a large, shallow quake beneath the seafloor. The Philippines is bordered by deep subduction trenches that can generate them — but most earthquakes do not. Here's how the hazard works and where to get official warnings.
Tsunamigenic trenches
3
offshore subduction sources
Recent tsunami flags
30
in the current catalog
Longest source
1,320 km
Philippine Trench
Max historical
M8
recorded on these trenches
What makes an earthquake tsunamigenic?
Three conditions usually have to come together. Most earthquakes are missing at least one of them, which is why tsunamis are relatively rare.
Large magnitude
Generally M7.0 or greater. The earthquake must displace a vast volume of water — smaller events rarely move enough seafloor.
Shallow & offshore
A shallow rupture (typically under ~70 km) beneath the ocean floor. Deep or on-land earthquakes seldom deform the seabed enough.
Vertical (megathrust) motion
Subduction-zone thrust faults push the seafloor up or down. This vertical displacement is what lifts the water column. Strike-slip motion rarely does.
Tsunamigenic sources around the Philippines
The country's tsunami risk comes mainly from these offshore subduction trenches, where one tectonic plate dives beneath another.
Philippine Trench
Max M8The Philippine Trench is a submarine trench east of the Philippines, reaching depths of 10,540 meters. It is the third deepest trench in the world.
Manila Trench
Max M7.6An oceanic trench west of the Philippines, capable of producing large megathrust earthquakes. It extends from Taiwan to Mindoro and poses tsunami risk to western Luzon.
Cotabato Trench
Max M7.8A submarine trench located in the Celebes Sea, south of Mindanao. It is a subduction zone where the Celebes Sea Plate subducts under the Sunda Plate.
Recent tsunami-flagged earthquakes
Events in the catalog that triggered a tsunami warning or observation. A flag does not mean a destructive wave occurred — many produce only minor sea-level changes.
97 km ENE of Miyako, Japan
2026 · 25 km deep
northern Mid-Atlantic Ridge
2026 · 10 km deep
233 km ESE of Attu Station, Alaska
2026 · 4 km deep
231 km ESE of Attu Station, Alaska
2026 · 8 km deep
170 km SE of Kirakira, Solomon Islands
2026 · 10 km deep
92 km S of Nikolski, Alaska
2026 · 17 km deep
223 km ESE of Attu Station, Alaska
2026 · 10 km deep
227 km ESE of Attu Station, Alaska
2026 · 10 km deep
229 km ESE of Attu Station, Alaska
2026 · 10 km deep
227 km ESE of Attu Station, Alaska
2026 · 10 km deep
93 km SW of Nikolski, Alaska
2026 · 8 km deep
96 km SW of Nikolski, Alaska
2026 · 14 km deep
57 km NNW of Kota Belud, Malaysia
2026 · 629 km deep
155 km N of Arecibo, Puerto Rico
2026 · 34 km deep
48 km W of Port-Olry, Vanuatu
2026 · 43 km deep
8 km NNW of Meadow Lakes, Alaska
2026 · 30 km deep
39 km E of Adak, Alaska
2026 · 61 km deep
295 km ESE of Attu Station, Alaska
2026 · 10 km deep
off the coast of Oregon
2026 · 10 km deep
280 km ESE of Attu Station, Alaska
2026 · 19 km deep
245 km NNW of Tobelo, Indonesia
2026 · 31 km deep
31 km ESE of Baculin, Philippines
2026 · 22 km deep
34 km ENE of Port Alsworth, Alaska
2026 · 189 km deep
0 km W of San Marcos, Mexico
2026 · 18 km deep
113 km NNW of Yakutat, Alaska
2026 · 5 km deep
111 km N of Yakutat, Alaska
2026 · 5 km deep
29 km ESE of Yilan, Taiwan
2025 · 63 km deep
108 km N of Yakutat, Alaska
2025 · 5 km deep
258 km ESE of Chiniak, Alaska
2025 · 10 km deep
117 km NE of Kuji, Japan
2025 · 19 km deep
FAQ
Tsunamis: frequently asked questions
What causes a tsunami?+
Most tsunamis are caused by large, shallow undersea earthquakes (typically M7.5+) that suddenly lift or drop the seafloor, displacing the water column above. Underwater landslides and volcanic eruptions can also trigger them.
What should I do during a tsunami warning?+
If you feel a strong or long earthquake near the coast, or an official warning is issued, move immediately to high ground or inland — don't wait for confirmation. A rapidly receding ocean is a natural warning sign. Stay away until officials declare it safe.
How fast does a tsunami travel?+
In the deep ocean a tsunami can travel as fast as a jet airliner — around 700–800 km/h — while being barely noticeable. As it reaches shallow water near the coast it slows down and its height builds dramatically.
What to do
- Feel a strong quake near the coast? If shaking is strong or lasts a long time, don't wait for an official warning — move to high ground or inland immediately.
- Heed natural signs. A sudden retreat of the sea, or a loud roar from the ocean, can precede a wave. Leave low-lying areas at once.
- Stay away until cleared. Tsunamis arrive as a series of waves; later ones can be larger. Return only when authorities say it is safe.
Official sources
Always rely on official agencies for tsunami warnings — this site is informational and is not a warning service.
- PHIVOLCS — Philippine Institute of Volcanology and Seismology, the national authority for local tsunami warnings.
- Pacific Tsunami Warning Center (PTWC) — issues basin-wide bulletins for the Pacific.