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Kobe Earthquake

Page created by: Liban Omar and Michael Mccloed and Jonathan Churchill.

Class:8PSY

· Introduction

· Facts about the Kobe Earthquake

Introduction

Where is Kobe? Kobe is in Japan.

Where in Japan? Kobe is in the southeast of Japan.

What type of country is Japan (Rich or Poor)? Japan is a rich country.

How do you know? I know because Japan makes most of the electronics goods around the world, if we compare it to other countries it has good health care and good education. It has a high G.N.P

Why does Japan have Earthquakes? They have earthquakes because they are on a plate boundary. Kobe is actually located on 3 different plate boundaries – where the Amurian plate, Pacific plate and Phillipines plate meet. These are all grinding and moving past each other causing tension and stress to build up.

Which plate is it on? The Phillipines plate, the Pacific plate and the Amurian plate.

What happens at plate boundaries? Plates can either move towards each other (DESTRUCTIVE), away from each other (CONSTRUCTIVE) or passed each other (CONSERVATIVE). Plates can bash into each other, scrape past each other or pull away. This causes earthquakes and volcanoes and tension and stress will build up in the earths crust (solid) and mantle (liqud molten rock). As the built up tension is released shockwaves ripple out from the epicenter (surface) or focus (below ground). These shockwaves cause the destruction, and if the crust splits molten rock is released at the surface as lava.

Facts about the Kobe Earthquake

Where was the epicenter of the Kobe Earthquake? Awaji Island, just off the south west of Kobe City.

Why is it more dangerous to be close to the epicenter? This is where the earthquake is at its most violent – the shockwaves are strongest here.

What is the Richter scale? This is a scale that measures earthquake strength. 10 is strongest and 1 is most weak. (see below)

What strength was Kobe? 6.9 on the Richter scale.

Earthquakes

On January 17, 1995, the Hyogoken-Nanbu (Kobe) earthquake struck the Hyogo prefecture of south-central Japan, resulting in over 5,400 deaths and injuries in the tens of thousands. The estimated damage costs approached 150 billion US dollars. A moderate to large earthquake (Mw 6.9), Kobe produced ground motions comparable to recent California events. But unlike the Loma Prieta and Northridge disasters, Kobe produced a fault rupture directly through the downtown section of a city. The setting of Kobe, with large strike-slip faults near a bay and engineered buildings constructed on sedimentary deposits, is not unlike that of the San Francisco Bay Area. The investigation of the Kobe earthquake is valuable in the characterization of near source ground motion in California and in the design of earthquake resistant structures worldwide.

What is a Richter scale?

The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included for the variation in the distance between the various seismographs and the epicentre of the earthquakes. On the Richter scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value.

At first, the Richter scale could be applied only to the records from instruments of identical manufacture. Now, instruments are carefully calibrated with respect to each other. Thus, magnitude can be computed from the record of any calibrated seismograph.

How can buildings be designed to withstand earthquakes?

You can make. Birdcage interlocking steel frame, identification number visible on the roof to allow easy access and to assess damage after an earthquake. Automatic shutters will also protect the occupants by coming down over the windows to prevent the widows blowing in or shattering on passing pedestrians. The building should also be anchored flexibly into a steel superstructure to allow the building to move with earth movements and tremors. The building should also be designed with open areas as a safe place for people to assemble after an earthquake or evacuation of a building. To allow the building to withstand the earthquake it can be constructed and reinforced with latticework foundations deep in the bedrock with rubber shock absorbers between the foundations and super-structure.