1. epicenter
the place on the earth’s surface just above the center of an earthquake
This diagram shows the epicenter of an earthquake.

2. Types of Waves Compression wave Transverse Wave Seismic Wave
Body Waves
Primary or p-wave
Secondary or s-wave
Transverse wave
Surface
Love wave
Rayleigh wave

3. Seismic Wave
Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs.
There are several different kinds of seismic waves, and they all move in different ways. The two main types of waves are body waves and surface waves.

4. Body Waves P Waves (compression wave)
The first kind of body wave is the P wave or primary wave. This is the fastest kind of seismic wave. The P wave can move through solid rock and fluids, like water or the liquid layers of the earth. It pushes and pulls the rock it moves through just like sound waves push and pull the air.

5. Stop and Think
Have you ever heard a big clap of thunder and heard the windows rattle at the same time?
The windows rattle because the sound waves were pushing and pulling on the window glass much like P waves push and pull on rock. Sometimes animals can hear the P waves of an earthquake. Usually we only feel the bump and rattle of these waves.

6. Body Waves S wave (transverse wave)
The second type of body wave is the S wave or secondary wave, which is the second wave you feel in an earthquake. An S wave is slower than a P wave and can only move through solid rock. This wave moves rock up and down, or side-to-side.

7. Surface Waves Love Waves
The first kind of surface wave is called a Love wave, named after A.E.H. Love, a British mathematician who worked out the mathematical model for this kind of wave in It's the fastest surface wave and moves the ground from side-to-side.

8. Surface Waves Rayleigh Waves
The other kind of surface wave is the Rayleigh wave, named for John William Strutt, Lord Rayleigh, who mathematically predicted the existence of this kind of wave in A Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is moving. Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves.

9. Seismic P (compressional) and S (shear)
wave propagation (both are body waves)

10. Seismic Rayleigh and Love wave
propagation (both are surface waves)

11. Other Characteristics
Characteristics of Seismic Waves
Table 2:  Seismic Waves
Type (and names)
Particle Motion
Typical Velocity
Other Characteristics
P,Compressional, Primary, Longitudinal
Alternating compressions (“pushes”) and dilations (“pulls”) which are directed in the same direction as the wave is propagating (along the raypath); and therefore, perpendicular to the wavefront
VP ~ 5 – 7 km/s in typical Earth’s crust;
    >~ 8 km/s in Earth’s mantle and core;  1.5 km/s in water; 0.3 km/s in air
P motion travels fastest in materials, so the P-wave is the first-arriving energy on a seismogram.  Generally smaller and higher frequency than the S and Surface-waves.  P waves in a liquid or gas are pressure waves, including sound waves.
S,   Shear, Secondary, Transverse
Alternating transverse motions (perpendicular to the direction of propagation, and the raypath); commonly polarized such that particle motion is in vertical or horizontal planes
VS ~ 3 – 4 km/s in typical Earth’s crust;
    >~ 4.5 km/s in Earth’s mantle;  ~  km/s in (solid) inner core
S-waves do not travel through fluids, so do not exist in Earth’s outer core (inferred to be primarily liquid iron) or in air or water or molten rock (magma).  S waves travel slower than P waves in a solid and, therefore, arrive after the P wave.

12. Characteristics of Seismic Waves
L,  Love, Surface waves, Long waves
Transverse horizontal motion, perpendicular to the direction of propagation and generally parallel to the Earth’s surface
VL ~  km/s in the Earth depending on frequency of the propagating wave
Love waves exist because of the Earth’s surface.  They are largest at the surface and decrease in amplitude with depth.  Love waves are dispersive, that is, the wave velocity is dependent on frequency, with low frequencies normally propagating at higher velocity.  Depth of penetration of the Love waves is also dependent on frequency, with lower frequencies penetrating to greater depth.
R,   Rayleigh, Surface waves, Long waves, Ground roll
Motion is both in the direction of propagation and perpendicular (in a vertical plane), and  “phased” so that the motion is generally elliptical – either prograde or retrograde
VR ~  km/s in the Earth depending on frequency of the propagating wave
Rayleigh waves are also dispersive and the amplitudes generally decrease with depth in the Earth.  Appearance and particle motion are similar to water waves.

13. A simple wave tank experiment – a ping pong ball is dropped onto the surface of the water; small aid viewing of the waves; distance marks on the bottom of the container allow calculation of wave velocity.

14. Seismic P (compressional) and S (shear)
wave propagation in the slinky

15. Tsunami Evacuation Map24

16. Possible large-scale earthquakes and tsunamis in Japan
Tokyo Inland EQ
Tokai EQ
Tonankai & Nankai EQ
I could say that we have been successful to some extent to reduce damage mainly from meteorological disasters like typhoons.
However, we are not be able to forecast earthquakes and other sudden on-set disasters in most cases so that they could cause severe damage in particular when they hit densely populated areas as we witnessed in the Kobe EQ.
It is also fact that there are wide areas spreading in Japan and off the coast with possible large-scale earthquake sources as shown in this map.
Japan Trench & Chishima Trench EQs 49

17. Japan and its major seacoasts
Chishima Trench
Japan Trench
Suruga Trough
200 km
400 km
600 km
800 km
1,000 km
Nankai Trough
Seismic areas for reinforcing and promoting disaster reduction measures related to the Tokai, Tonankai and Nankai Earthquakes
District (undesignated) for promoting seismic disaster reduction measures related to earthquakes along the Japan Trench and the Chishima Trench 48

18. Sign of Previous Tsunami Height (2)
Inundated level of previous Tsunami 23

19. Promoting Basic Knowledge about “TSUNAMI” Disaster+
Safe Evacuation Route
Early Warning =
Understanding of Hazardous Areas
Appropriate Risk Awaweness of Local Communities
Safe Evacuation 16

20. Tsunami Evacuation Area Tsunami Evacuation Building
Pictogram on Tsunami
Tsunami Hazard Area
Tsunami Evacuation Area
Tsunami Evacuation Building
Safe place/hill for evacuation
against Tsunami.
Building for evacuation
against Tsunami.
There is a high possibility to
be flooded in this area
when earthquake occurs. 21

21. Magnitude in Richter Scale Energy Released in Joules Comment
2.0
1.3 x 108
Smallest earthquake detectable by people.
5.0
2.8 x 1012
Energy released by the Hiroshima atomic bomb.
7.6 x 1013 to 1.5 x 1015
About 120 shallow earthquakes of this magnitude occur each year on the Earth.
6.7
7.7 x 1014
Northridge, California earthquake January 17, 1994.
7.0
2.1 x 1015
Major earthquake threshold.
7.4
7.9 x 1015
Turkey earthquake August 17, More than 12,000 people killed.
7.6
1.5 x 1016
Deadliest earthquake in the last 100 years. Tangshan, China, July 28, Approximately 255,000 people perished.
8.3
1.6 x 1017
San Francisco earthquake of April 18, 1906.
9.3
4.3 x 1018
December 26, 2004 Sumatra earthquake.
9.5
8.3 x 1018
Most powerful earthquake recorded in the last 100 years. Southern Chile on May 22, Claimed 3,000 lives.