Geohazard. Chona Mae

Question 1

This earthquake generated a tsunami that swept across the Indian Ocean, killing an estimated 225,000 people.

Answer 1

Magnitude 9.1 Indonesian earthquake in December 26, 2004

Question 2

Is a very long-wavelength wave of water that is generated by sudden displacement of the seafloor or disruption of any body of standing water. Sometimes called as “seismic sea waves”

Answer 2

Tsunami

Question 3

True or False. Tsunami is a series of multiple waves

Answer 3

True

Question 4

The distance between three wave crests is 240 meters. Determine the wave base.

Answer 4

Answer: 60 meters
Wavelength: 120 meters

Question 5

______ is the distance between 2 consecutive wave crests or 2 consecutive wave troughs. ______ meters is its value in normal ocean waves.

Answer 5

Wavelength. 100.

Question 6

True or False. High energy wave is defined by shorter wavelength AND lower amplitude.

Answer 6

False. High energy wave = short wavelength (or high frequency) + high amplitude

Question 7

refers to the distance between the trough of the wave and the crest of the wave

Answer 7

Wave height

Question 8

height of the wave above the still water line, usually this is equal to 1/2 the wave height.

Answer 8

Wave amplitude

Question 9

amount of time it takes for one full wavelength to pass a stationary point

Answer 9

Wave Frequency or Period

Question 10

Can tsunamis be created in a man-made earthquake?

Answer 10

Yes

Question 11

What movement/displacement mechanism in earthquakes is important to generate tsunami?

Answer 11

Vertical displacement

Question 12

What is the velocity of the wave if it has 500 km wavelength and it takes 2 hours for one full wavelength to pass a stationary point

Answer 12

Velocity = wavelength / period
Velocity = 250 km/hr

Question 13

Velocities of normal ocean waves are about _________

Answer 13

90 km/hr

Question 14

If the trough of the tsunami wave
reaches the coast first, this causes a
phenomenon called ___________,
where it appears that sea level has
dropped considerably

Answer 14

Drawdown

Question 15

If the crest of the tsunami wave
reaches the coast first, this causes a
phenomenon called ___________,
where it appears that sea level has
risen considerably

Answer 15

Run-up

Question 16

is a standing wave in an enclosed or partially enclosed body of water. Also termed as “Lake Tsunamis”

Answer 16

Seiche

Question 17

What depth and magnitude of earthquakes is important to generate tsunami?

Answer 17

Shallow (<70km) and at least M6.5 on Richter Scale

Question 18

Which phenomenon do not generate tsunami.
1. Volcanic eruption
2. Landslide
3. Surface Waves
4. Nuclear Tests
5. Meteorite Impacts
6. Underwater Explosions
7. Subduction Zone Earthquakes

Answer 18

3. Surface Waves. Although surface waves generate ocean waves, it is not enough force to generate tsunamis.

Question 19

• Mw 7.3 earthquake occurred near Unimak Island in the Aleutian Islands west of Alaske, near the Alaska Trench
• Sediment accumulating in the trench slumped into the trench and generated a tsunami

Answer 19

April 1, 1946 Alaskan Tsunami

Question 20

True or False. Tsunamis are waves that are generated to travel towards the nearest coast.

Answer 20

False. Tsunamis are waves that are generated to travel in ALL DIRECTIONS. Like ripples in a pond.

Question 21

• Mw 9.5 earthquake occurred along the subduction zone off South America
• Also known as the “Great Chilean Earthquake”
  The first tsunami wave had a run-up of 4.5 m whichhit the coast of Chile. But, about 1 hr. later, the second wave traveling at a velocity of 166 km/hr crashed in with a run-up of 8 m.
• a third wave traveling at only 83 km/hr that crashed in later with a run-up of 11 m
• causalities listed: 909 dead with 834 missing

Answer 21

May 22, 1960 Valdivia Earthquake and Tsunami

Question 22

• Mw 9.2 earthquake occurred along the subduction zone off of Alaska
• caused deformation of the crust where huge blocks where dropped down as much as 2.3 m
• Sediment accumulating in the trench slumped into the trench and generated a tsunami

Answer 22

March 27, 1964 Good Friday Earthquake in Alaska

Question 23

• Mw 8.1 earthquake generated along the Cotabato Trench
• Up to 4.5-meter high waves
• devastated more than 700 kms of coastline bordering Moro Gulf in the North Celebes Sea

Answer 23

August 17, 1976 Moro Gulf Earthquake

Question 24

True or False. The first wave in a series of wave in a tsunami event is not always the strongest.

Answer 24

True. May 22, 1960 Valdivia Earthquake and Tsunami produced its strongest wave on the third wave

Question 25

The eruption of __________in the Straights of Sunda, between Java and Sumatra, in 1883 generated at least three tsunami that killed 36,417 people.

Answer 25

Krakatau

Question 26

True or False. Formation of a Caldera (a collapse of a volcanic island) can trigger tsunamis.

Answer 26

True

Question 27

Aside from volcanic earthquakes, what other volcanic phenomena generates tsunami?

Answer 27

Explosive eruptions can rapidly emplace pyroclastic flows into the water, LANDSLIDES AND DEBRIS AVALANCES produced by eruptions can rapidly move into water, displacing water and creating tsunamis.

Question 28

Nuclear testing by the United States in the Bikini Atoll in Marshall Islands in the 1940s and 1950s generated up to ______-m high tsunamis

Answer 28

30

Question 29

the apparent impact of a meteorite at the end of the Cretaceous Period, about 65 million years ago near the tip of what is now the ________________, produced tsunami that left deposits all along the gulf coast.

Answer 29

Yucatan Peninsula of Mexico

Question 30

What administration has set up a warning system for areas in the Pacific Ocean, called the ___________________?

Answer 30

National Oceanic and Atmospheric Administration (NOAA); Pacific Tsunami Warning Center

Question 31

Are passive margins safe from tsunamis?

Answer 31

No

Question 32

Two mitigation measures for Tsunami

Answer 32

1. Prediction And Early Warning
2. Tsunami Safety Rules