Seismicity 2
- Created by: Sharon
- Created on: 30-12-15 17:14
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- Seismicity 2
- Short Term Prediction
- monitoring processes signify quakes
- Hard as deep in surface & no patterns
- anomalous/proced quakes "precursor"
- Ground uplift - swelling rokcs - cracks rocks
- Forechocks
- Water level - pressure increases force water up or down.
- emission radon - decay uranium, strain causes deformation and release.
- animal behavior - snakes not in holes, panda screaming
- monitoring processes signify quakes
- Mitigating
- "quakes don't kill, buildings do"
- California strict building codes 1986 40 died in 7.1 Armenia no codes 25,000 died 10 months later
- 2010 Haiti 250,000 - Feb 27 Chile where are codes only 520
- Japan City resistent/awareness/improve prediction./evacuation routes/laws in 07/oberservation areas/spare supplies always/smart metre turns of gas/insurance just for earthquake
- Risk
- depends on whether tectonic activity occurs in area.
- US greatest, San Andreas,
- If before likely to happen again
- Controlling
- No attempt control. Known to be cause by humans = possible to control
- Hoover Dam fluid pressure = 600 quakes
- Nuclear testing Nevada = 6.3
- Increase magnitude = 30 fold increase energy (8.0=7.0x30)
- Where
- Distribution and frequency "seismicity"
- Shallow focus - Focal depth >70km
- Deep focus - focal 700km
- Diverging
- Move away/lithosphere tensional stress/shallow quakes
- Converging
- run into/compressional stress
- Subduction - oceanic under continental - lithosphere cold=descend brittle=fractures=quakes
- Collision - 2 continental collide.
- run into/compressional stress
- Long term forecasting
- Knowledge when&where have occurred.
- Paleoseismology - prehistoric quakes, determine reoccurance intervals
- Seismic gaps - zone along tectonically active area no quakes recently, known strain is building
- Short Term Prediction
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