Tsunamis Flashcards
When was the 2004 Indonesian Earthquake and Tsunami, and what magnitude was it?
December 24, 2004
magnitude 9.1
2004 Indonesian earthquake generated a _____ that swept across the ____
tsunami ; Indian Ocean
What city was the closest to the epicenter of the 2004 Indonesian earthquake?
Banda Aceh
a very long-wavelength wave of water that is generated by sudden displacement of the sea floor or disruption of any body of standing water
tsunami
what is a tsunami
a long-wavelength wave of water generated by sudden displacement of the sea floor and disruption of body of standing water
tsunamis are sometimes called as
“seismic sea waves”
t or f: tsunamis occur suddenly, and often without warning
T
what are the parts of wave
wavelength, wave height, amplitude, wave frequency or period, velocity
it is the distances between wave and crests
wavelength
normal ocean waves have about ___ wavelength
100m
tsunami waves have about ____ wavelength
500 km
t or f: the rate at which wave loses its energy is directly proportional to the wavelength
F (inversely proportional)
refers to the vertical distance between the trough and crest of the wave
wave height
equals to 1/2 of wavelength
wave amplitude
wave amplitude is the height of the wave above the ____
still water line
amount of time it takes for one full wavelength to pass a stationary point
wave frequency or period
wind generated wave usually have a period of ___
5 to 20 seconds
tsunami generated waves have a period of
10 minutes to 2 hours
velocities of normal ocean waves are about
90 km/hr
velocity of tsunami waves
950 km/hr
waves move much more rapidly across
ocean basins
formula for velocity of wave
velocity = wavelength / period
when the ocean is 6100 m deep, a tsunami will travel at about what velocity?
890 km/hr
if the trough of the tsunami reaches the coast first sea level will _____, causing a ______
drop ; drawdown
if the crest of the tsunami reaches the coast first, sea level will ____, causing a ___
rise ; run-up
t or f: one coastal area may see no damaging wave activity while in another area destructive waves can be large and violent
T
tsunamis can be generated by (5 phenomena)
earthquakes, volcanic eruptions, landslides, underwater explosion, and meteorite impact
earthquakes can cause tsunami by causing a
disturbance of the seafloor
controlling factors of earthquake generated tsunami
magnitude, type of displacement, epicenter
most tsunamis are generated by earthquakes that occur along _____ boundaries along the _____
subduction zone boundaries
oceanic trenches
how are tsunamis generated in subduction zones
colliding plates get stuck
overriding plate gets distorted
plates rupture, releasing earthquakes
ocean floor gets pushed up, displacing large volume of water
Indian Ocean Tsunami was along the oceanic trench off the coast of
Sumatra, Indonesia
when was the alaskan tsunami and what magnitude earthquake was it
april 1, 1946
magnitude 7.3
Valdivia Earthquake and Tsunami, date and magitude
May 22, 1960
magnitude 9.5
height and velocity of the three tsunamis that occurred in Chile
4.5 m
8 m ; 166 km/hr
11 m; 83 km/hr
the Valdivia earthquake was also known as
“The great Chilean Earthquake”
Good Friday Earthquake in Alaska
March 27, 1964
M 9.2
displacement of the block in good friday earthquake
2.3m vertical
Moro Gulf Earthquake, date, magnitude, height of wave
August 17, 1976
m 8.1
4.5 m
t or f: collapse of volcanoes to form calderas can suddenly displace water, therefore generating earthquakes
True
Explosive eruptions can rapidly emplace ______ into the water, _____ and ______ produced by eruptions can rapidly move into water
pyroclastic flows
landslide
debris avalanche
at least how many tsunamis were generated during the Mt. Krakatau Volcanic eruption in 1883
three
the Krakatau eruption was a _____ type of eruption, generating a ____ height eruption column into the atmosphere
Plinian
40 km
t or f: a loud explosive blast heard as far away as Australia occurred during Krakatau eruption
T
_____ fell into Lituya Bay, Alaska in ___ causing a wave with a run-up of about _____ m
Debris avalanche
1958
60m
about 65 million years ago at the end of the _____ period, apparent impact meteorite occurred in ______
Cretaceous
Yucatan Peninsula of Mexico
the meteorite impact in Yucatan Peninsula produced tsunami that left deposits all along the ________ and the _______
Gulf Coast of Mexico ; United States
meaning of NOAA
National Oceanic and Atmospheric Administration
t or f: areas located at great distances from earthquakes that could potentially generate a tsunami usually have PLENTY of time for warnings to be sent and coastal areas evacuated
T
it is a good example of areas located far from most of the sources of tsunami
Hawaii
Pacific warning system for areas in the Pacific ocean
Pacific Tsunami Warning Center
Pacific Tsunami Warning Center consists of networks of ____ and ____ around the ____
seismograph stations
tidal stations
Pacific Basin
where is the center of PTWC located
HAwaii
before the Japanese warning system ___ tsunamis killed over 6000 people in Japan. Since the establishment of the warning system ___ tsunami have killed 215
14
20
meaning of JICA
Japan International Cooperation Agency
t or f: the upper floors of high, multi-story, REINFORCED concrete hotels can provide refuge if there is no time to quickly move inland to the higher ground
T
how many philippine tsunami network were detected by JICA
32
approaching tsunamis are sometimes heralded by ____ or ____ of coastal waters
rise
fall
nuclear testing by the united states in the ______ in ____ islands in the 1940s and 1950s generated up to ____ high tsunamis
bikini atoll
marshall islands
30 m
