Theme 3: Nat Haz - Hazard Protection

Case Study 7: Hazard Protection

Volcanic Eruption: e.g. Mt Pinatubo eruption 9-16th June 1991

Protection / Warnings:
1. USAF (Clark Air Base) nearby
2. Seismometers - measured 400 earthquakes in 2 days
3. Tilt Meters measured the bulge of the volcano cone
4. Sulphur readings registered lower levels of the gas being released (plug/dome blocking the vent)
5. Steam, gas being released

= warn people
= evacuate 12,000 USAF personnel from Clark Air Base
= evacuate locals e.g. Aeta Tribe who lived on flanks of the volcano
= set up refugee camps for displaced locals (100,000 people without homes)
= only 70 deaths as a direct result of the volcanic eruption (600 more due to disease, Lahars (mudflows and contaminated water supplies)

Earthquakes:

Protection / Warnings:

1. Design of buildings e.g. Transamerica Building in San Francisco (wide base, narrow top)

• using steel instead of brick
• fire resistant materials
• shutters to stop glass from shattering
• deep foundations built on solid bedrock (many buildings in San Francisco [1989] collapsed after being built on unstable bedrock)
• crossing the steel structure to reinforce the building
• rubber foundations to allow the building to sway
• weighted foundation to pull the building back from a sway during the earthquake
• In India testing the buildings by putting them on platforms and pulling the platform backwards and forwards with tractors to simulate an earthquake
• In Peru the government has trained people to build the housing from materials such as Bamboo and mud to ensure that if they collapse they don't cause as much damage
• In Japan the 1st September is Disaster Day - a national holiday where they practise procedures of evacuation and response in case of an earthquake
• In California they have earthquake kits in public buildings and advise on what to do via leaflets and t.v/radio broadcasts as well as educating children in Primary school

Predicting earthquakes is still not possible, yet scientists study earth movements, they look at previous history, they try to work out the average length of time between earthquakes and try to determine where on a plate boundary pressure will be building to predict where the next earthquake will be.

= 1989 San Francisco earthquake (Loma Prieta epicentre)

- 7.1 on the Richter Scale

- 68 killed

- 0ver 4000 injured

- 0ver 12,000 homeless

- main roads, highways disrupted

- buildings collapsed (Marina District near Fisherman's Wharf - due to unstable bedrock)

- fires broke out (Marina District due to gas pipes rupturing)

- $10 billion damage