The San Francisco Earthquake, 1989 LO: to be able to explain the cause and effects of the earthquake (on the people, environment and economy)

Remember to get full marks in a case study answer you need to learn specific facts and figures and include locational detail (i.e. name specific places, areas, buildings etc. affected).

Details…. 17th October 1989, at 5.04 pm, an earthquake measuring 6.9 on the Richter scale, and lasting only 15 short, but devastating seconds, hit San Francisco

Watch the video https://www.youtube.com/watch?v=T1KuNY6WDe8 Make notes on the: Cause Effects Response Any facts, figures

Cause

CAUSES OF THE EARTHQUAKE Shockwaves from an earthquake http://www.youtube.com/watch?v=_YLjIvJXhpg The San Andreas fault (conservative plate boundary) http://www.youtube.com/watch?v=ZxPTLmg0ZCw

Cause San Francisco is located at a conservative plate margin where convection currents in the mantle are causing the Pacific and North American plates to slide past each other. The Pacific plate is moving in a NW direction relative to the North American plate. The San Andreas fault is an 800 mile long crack in the earth’s crust between the two plates. Pressure was building up on the northern segment of the fault due to friction between the plates. The earthquake occurred when the crustal rocks comprising the Pacific and North American Plates abruptly slipped by as much as 2 metres. The focus of the earthquake was at a depth of 11 miles and was beneath the Santa Cruz mountains, located 9 miles NE of Santa Cruz and 60 miles south of San Francisco. At 5.04pm on October 17th 1989 the built up pressure was released amounting to 6.9 on the Richter Scale. The shockwaves of the earthquake were felt most strongly at the epicentre, directly above the focus, at a mountain called Loma Prieta.

Choose one of these 6 mark questions For an earthquake you have studied explain the causes. For an earthquake you have studied explain the effects.

The effects of the 1989 earthquake included: - 68 Deaths - 6,000 Homes damaged / destroyed - 2000 people made homeless - Upper deck of the Nemitz highway collapsing onto the lower deck crushing people in their cars - A section of the San Francisco-Oakland Bay Bridge collapsing - Fire resulting from gas explosions - Massive economic costs ($4.4 billion) - Damage to infrastructure - electricity / gas and water mains cut

3 Areas in San Francisco were particularly badly affected: 1. The Marina / Bay District Here the buildings were wooden and not securely attached to their foundations. The area was also located on an old landfill site, which was created following the devastation caused by the 1906 earthquake. Liquefaction occurred. This is where as the ground acted more like a liquid as water moved up through the sediments resulting in reduced strength and causing buildings to collapse due to lack of support.

Liquefaction A condition where soil flows like a liquid. This caused extensive damage in the area including the collapsed overpasses and freeways.

2. Collapse of the Double-Decker Nimitz Highway and San Francisco-Oakland Bay Bridge A number of roadways were damaged during the earthquake, including the collapse of the upper tier of the double-decker Nimitz Highway (Interstate 80) onto the lower deck, killing and trapping motorists in their cars. The collapse was caused partly by soil weakness and also the unsuitable design of the supporting piers. A section of the Bay Bridge also collapsed killing motorists.

3. Older buildings Many of the older (50-100 year old) buildings which were not designed to withstand earthquakes were most severely damaged. Low rise building were also worse affected than taller buildings which swayed with the quake / ground motions.

Choose one of these 6 mark questions For an earthquake you have studied explain the causes. For an earthquake you have studied explain the effects.

News report script Task: Write a script for a news report about the 1989 San Francisco Earthquake including the characters below. Use research to support your own ideas. If you want to you may film the news report or you may perform it to the class. Either way you should hand in a full script of the contents of the broadcast. If preferred you can opt to write an individual news paper report covering the same topics as below. News presenter - you are located in the studio. You will read the headlines and give some background to the event, explaining what has happened and giving the location. You then hand over to the roving reporter at the scene. Roving reporter- you are at the scene of the earthquake. You will be interviewing the seismologist and the eye witness. You need to think up some questions to ask them. Ask the seismologist about the causes of the earthquake, and the eye witness about the effects. Seismologist - you will need to research the causes of the earthquake. The roving reporter will ask you some questions about this - make sure you find out what they are so that you can prepare your answers. Eye witness - you will need to find out about the effects of the earthquake, make sure you include plenty of detail. The roving reporter will ask you some questions about this - make sure you find out what they are so that you can prepare your answers. Finally the news reporter should include a summary of the events of the earthquake including the causes and the effects of the quake for San Francisco and the wider area. It would also be advisable to use pictures, graphs, diagrams and video clips to enhance your work – but remember to explain why they are there.

Earthquake preparedness http://quakequizsf.org/