Waves Swell, Surf, and Tides
Tsunamis
Tsunamis Waves of Destruction
Seismic Sea Waves
Seismic Sea Waves Most tsunamis are generated by earthquakes
Seismic Sea Waves Most tsunamis are generated by earthquakes However, most earthquakes do not generate tsunamis
Seismic Sea Waves Most tsunamis are generated by earthquakes However, most earthquakes do not generate tsunamis Tsunamis are generated when earthquakes fault the sea floor and displace seawater
When one side of a fracture moves up or down, seawater is displaced and a wave is generated
When one side of a fracture moves up or down, seawater is displaced and a wave is generated
Tsunami Characteristics
Tsunami Characteristics Wavelengths can be greater than 100 km
Tsunami Characteristics Wavelengths can be greater than 100 km Wave speeds can be greater than 700 km/hr
Tsunami Characteristics Wavelengths can be greater than 100 km Wave speeds can be greater than 700 km/hr Typical wave periods are 12-15 minutes
Tsunami Characteristics Wavelengths can be greater than 100 km Wave speeds can be greater than 700 km/hr Typical wave periods are 12-15 minutes Wave heights in the open ocean average 1 m
Tsunamis in Deep Water
Tsunamis in Deep Water Tsunami waves generally are undetectable by ships in deep water
Tsunamis in Deep Water Tsunami waves generally are undetectable by ships in deep water Sea level will rise and lower 1 m in 12-15 minutes
Tsunamis in Shallow Water
Tsunamis in Shallow Water Tsunami wave heights can increase significantly in nearshore, shallow water
Tsunamis in Shallow Water Tsunami wave heights can increase significantly in nearshore, shallow water However, most tsunamis wave do not break like normal wind waves
Tsunamis in Shallow Water Tsunami wave heights can increase significantly in nearshore, shallow water However, most tsunamis wave do not break like normal wind waves Tsunami wave crests can out run the troughs and form a wall of water separating different sea levels
Tsunamis in Shallow Water Tsunami wave heights can increase significantly in nearshore, shallow water However, most tsunamis wave do not break like normal wind waves Tsunami wave crests can out run the troughs and form a wall of water separating different sea levels The wall of water is called a tsunami bore
Tsunami Bore
Tsunami Runup
Tsunami Runup Runup is the height above sea level that a wave reaches as it runs up the coastline
Tsunami Runup Runup is the height above sea level that a wave reaches as it runs up the coastline Tsunami waves slow in shallow water but often strike a coastline at speeds greater than 50 mph
Tsunami Runup Runup is the height above sea level that a wave reaches as it runs up the coastline Tsunami waves slow in shallow water but often strike a coastline at speeds greater than 50 mph Along flat coastlines, tsunamis waves can travel inland for several miles
Tsunami Runup Runup is the height above sea level that a wave reaches as it runs up the coastline Tsunami waves slow in shallow water but often strike a coastline at speeds greater than 50 mph Along flat coastlines, tsunamis waves can travel inland for several miles When a wave retreats, it drags debris and humans into the ocean
Recent Hawai i Tsunamis
Recent Hawai i Tsunamis Historically, a large, deadly tsunami strikes the Hawaiian Islands every 25 years
Recent Hawai i Tsunamis Historically, a large, deadly tsunami strikes the Hawaiian Islands every 25 years The last two were in 1946 and 1960
Recent Hawai i Tsunamis Historically, a large, deadly tsunami strikes the Hawaiian Islands every 25 years The last two were in 1946 and 1960 Hawai i is overdue statistically for a large, destructive tsunami
April 1, 1946
April 1, 1946 A 7.8 magnitude earthquake in the Aleutian Islands generated a Pacific-wide tsunami
April 1, 1946 A 7.8 magnitude earthquake in the Aleutian Islands generated a Pacific-wide tsunami 159 people died in Hawai i
April 1, 1946 A 7.8 magnitude earthquake in the Aleutian Islands generated a Pacific-wide tsunami 159 people died in Hawai i The runup was 12.0 m in Pololu Valley
Travel time in hours
Hilo 1946
May 22, 1960
May 22, 1960 A 9.5 magnitude earthquake in Chile generated a Pacific-wide tsunami
May 22, 1960 A 9.5 magnitude earthquake in Chile generated a Pacific-wide tsunami 61 people died in Hawai i
May 22, 1960 A 9.5 magnitude earthquake in Chile generated a Pacific-wide tsunami 61 people died in Hawai i The runup in Hilo Bay was 10.7 m
Travel time in hours
Hilo 1960
All pau!!!