Where tectonics meets people: Tsunamis

Tsunami

A large ocean wave caused by undersea earthquakes, landslides, volcanic eruptions, or meteorite impacts.

Harbor Wave (Tsunami Origin)

The word “tsunami” comes from Japanese words meaning “harbor” and “wave,” referencing its devastating coastal impact.

Shield Volcano (Hawaii)

Broad, gently sloping volcanoes formed by low-silica lava; steep underwater slopes can collapse and trigger tsunamis.

Anomalous Coral Deposits

Coral and beach debris found far above sea level on Hawaiian islands, evidence of ancient mega-tsunamis.

Submarine Landslide

An underwater slope failure that displaces water and can generate massive tsunamis.

Goleta Landslide (CA)

A prehistoric underwater landslide off California that likely triggered a tsunami thousands of years ago.

Wave Transformation

As a tsunami enters shallow water, its long, low wave compresses into a short, high surge due to friction with the ocean floor.

Tsunami Trough Effect

The initial retreat of water before a tsunami wave arrives, often luring people into danger.

Indian Ocean Tsunami (2004)

A devastating tsunami triggered by a massive earthquake, killing ~230,000 people across multiple countries.

Lisbon Earthquake (1755)

A powerful quake and tsunami that killed ~60,000 people in Portugal, Morocco, and Spain.

Krakatau Eruption (1883)

A volcanic explosion in Indonesia that generated tsunamis felt as far as England, killing ~40,000.

Santorini Eruption (1600s BCE)

A volcanic event that may have caused a tsunami contributing to the fall of the Minoan civilization.

Lituya Bay Tsunami (1958)

A landslide-induced wave in Alaska that reached 1,800 feet high, the tallest tsunami ever recorded.

Seismometer

An instrument that detects Earth’s shaking and helps trigger tsunami warnings.

Natural Buffers

Coral reefs and coastal vegetation that reduce tsunami impact; their destruction increases vulnerability.

Zoning Codes

Regulations that guide safe building practices in tsunami-prone areas to reduce risk.

2004 Indian Ocean Tsunami

One of the deadliest natural disasters, triggered by a massive earthquake and killing over 300,000 people.

Lampuuk (Indonesia)

A village hit by the 2004 tsunami, where water surged up to 28 meters (100 feet) above normal sea level.

High-Water Mark (Tsunami)

The maximum inland height reached by a tsunami, often visible through tree damage and debris lines.

Tsunami Force

The immense energy of a tsunami capable of breaking steel-reinforced beams and uprooting trees.

Sand Deposition (Lampuuk)

Evidence of tsunami activity where 73 cm (2 ft) of sand was deposited inland over dark soil.

Tsunami Sediment Record

Layers of sand and debris left by past tsunamis, used by geologists to study tsunami frequency.

1964 Alaska Earthquake

A major quake that triggered deadly tsunamis via plate motion and underwater landslides.

Seward Damage (1964)

A town in Alaska where tsunami waves caused extensive destruction following the earthquake.

Prince William Sound Tsunami

A wave that splintered trees up to two feet in diameter, caused by an underwater landslide.

Trans-Alaska Pipeline

A major infrastructure project built after the 1964 quake, ending near Prince William Sound.