Lecture 8- Tsunamis

Question 1

What three things typically generate tsunamis?

Answer 1

1. Submarine Eq/ volcanoes
2. Submarine/into sea landslides
3. Comets or meteorite impacts

Question 2

What is tsunami wave velocity a product of?

Answer 2

Earths velocity and sea depth

Question 3

What is the equation linking amplitude and velocity?

Answer 3

A2V= constant

Question 4

What happens to H and V as waves get progressively inshore?

Answer 4

H decreases ,which in turn causes a decrease in V and an INCREASE IN A
Essentially: the wave gets slower but taller

Question 5

What is the typical velocity fo an offshore tsunami?

Answer 5

Up to 900km/hour

Question 6

What is the average amplitude of an offshore tsunami?

Answer 6

<2m

Question 7

What Is the average wavelength of an offshore tsunami?

Answer 7

Hundreds of Km

Question 8

What is the average velocity fo a near shore tsunami?

Answer 8

Few tens of kms

Question 9

What is the average amplitude of nearshore tsunamis?

Answer 9

Several tens of KM

Question 10

What is tsunamirun-up?

Answer 10

The maximum height above sea level reached by tsunami waves as it rushes on shore

Question 11

What is Unami inundation?

Answer 11

The horizontal distance reached by a tsunami, measured from the shoreline

Question 12

Where do 59% of all earthquakes occur?

Answer 12

In the Pacific ring of fire

Question 13

Where to 25% of tsunamis occur?

Answer 13

In the Mediterranean Sea

Question 14

What are the three ways of reducing vulnerability to tsunamis?

Answer 14

1. Hazard assessment (probabilistic forecasting)
2. Land use planning +defence
3. Education, planning, training

Question 15

What magnitude earthquake “guarantees” a tsunami event?

Answer 15

> 6.5

Question 16

What is issued when an earthquake magnitude 6.5 or greater occurs?

Answer 16

Bulletins

Question 17

What is issued when earthquakes 7.1-7.5 occur?

Answer 17

Watch bulletins

Question 18

What are dart bois?

Answer 18

Pressure recorders that are able to distinguish between long tsunami inundation and natural short wavelength ones

Question 19

How many countries are covered in the Pacific Tsuanami waning system?

Answer 19

28

Question 20

When was japans tsunami warning system established?

Answer 20

1952

Question 21

How many people died in the 2004 Indian Ocean tsunami? Why?

Answer 21

290000+ as there was no early warning system

Question 22

How quickly within a tsunami event does the Japanese tsunami warning system issue an alert?

Answer 22

Three minutes

Question 23

When was the pacific tsunami warning system implemented, how many countries are included and how long does data analysis tke?

Answer 23

Established in 1949, includes 28 countries and takes 10-20 minutes to process data

Question 24

Why does the tsunami blind zone occur in the pacific tsunami warning system?

Answer 24

Gaps in dart buoy distribution (particularly close to the coastline)