14.4 Earthquakes Small Case Studies Examples Flashcards
(5 cards)
What was the importance of the Pisir, Greece earthquake?
15 people died and hundreds were seriously injured- Pisir, Feb 1981.
High number of ancient architecture and also whole cities have been destroyed due to earthquakes here. E.g.. Helike- temple of Apollo destroyed by an earthquake. Moreover, Colossus of Rhodes, Greece (one of the seven ancient wonders of the world) was destroyed during an earthquake never to be seen again- 226 BC.
What was the importance of the San Francisco earthquake?
San Francisco Earthquake- April 18, 1906.
“Birth of Seismology”
Magnitude 7.9
Quake lasted for 45 seconds.
Gas mains burst and fires burnt out of control for 3 days.
Was one of the worst natural disasters in American History.
“Birth of Seismology”- breakthrough for geologists on how earthquakes occur.
City is perched on one of the most unstable fault lines in the world- San Andreas Fault.
In first few seconds many people died- crushed.
Shaking set church bells ringing
The aftermath of the earthquake killed up to 6,000 people and left more than 200,000 homeless.
San Andreas Fault- where two massive tectonic plates meet and are slowly moving past each other all the time.
1906- two sided of the fault line had moved past each other in a consistent pattern.
What was the importance of the Shaanxi, China earthquake?
The worlds deadliest earthquake.
Magnitude 8.
Freezing winters, hot summers- to cope with extreme temps Locals have burrowed into the hillside creating caves or Yardongs. Today, 40 million Chinese people still live in these types of caves. Silky soil is used which can be highly unstable- collapses easily.
What was the importance of the Mexico earthquake?
8.1 Magnitude
Parts of the city sit on an old drained lake bed- highly unstable- mixture of soft sand and clay soil- full of water.
Big skyscraper here (Torre Mayor)- 225 metres high
Sept 19th 1985- Mexico city struck by a massive earthquake- worst earthquake in mexico city.
9000 people died and 30,000 were injured.
Greatest destruction at the old lake bed- soft sediment bed amplified the shock waves- more destructive- cracked foundations of buildings- vibrations that shook their destruction- Liquefaction occurred- buildings slipped into the ground.
The Torre Mayor has foundations 60m deep, and also has a network of super diagonal diamond braces as an internal structure- at each junction there are 4 shock absorbers- these decrease shockwaves and absorb their energy.
What was the importance of the Turkey earthquake?
“Forecasting the future”.
North Anatolian Fault.
7.4 Magnitude
Lasted 45 seconds
25,000 people died
There is a Faultline that stretches across the country for 1500knm- one of the most dangerous faults on the planet. Millions of people live along its path.
Runs in a relatively straight line- easier for scientists to predict as long as you know where the stress from the last earthquake has travelled to- epicentre for the next one.
1998- calculated the next earthquake would be in the province of Kocaeli, Izmit Bay, where there was a population of 500,000 people. They could not tell when.
August 1999, 1 year after the prediction- earthquake occurred.
