Tsunamis - ESSC 101

Tsunami

Waves caused by rapid displacement of a large volume of water

What can tsunamis result from?

Earthquakes, volcanic eruptions, landslides, impacts

Risk zone

All coastal areas at risk

What areas are at the most risk of a tsunami?

Major subduction zones

How do earthquakes generate tsunamis?

Ocean floor is moved, creating rapid movement of water

Upward displacement

Plate shifting causes a mound of water to form, pushing it upwards

Downward displacement

Plates shift to create a depression for the water rush into, causing waves to form

Local tsunami

Earthquake occurs near land; the waves hit land quickly

Landslide tsunami

Second-biggest cause of tsunamis, often triggered by earthquakes

How do landslide tsunamis occur?

Material from landslide changes the ocean floor, producing a mound of water

Volcano induced tsunami

Volcanic blasts create avalanche of material into ocean, forming a mound of water

How does impact relate to tsunamis?

Impact of an object onto water can cause a tsunami

Runup

Highest vertical distance above normal sea level by the largest wave of a tsunami

Inundation

Longest horizontal distance inland from the largest wave of the tsunami (dry land getting covered)

Sea walls

Walls are built to try blocking tsunamis

Vegetation barriers

Dissipate energy of water movement to make waves less damaging

Secondary effects of tsunamis

Fires, water system damage, bad drinking water, coastal erosion

Tsunami detection

Network underneath ocean in which a signal is sent if a wave passes over the sensor