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Earthquakes case studies Sichuan, China Where? The Great Sichuan earthquake or Wenchuan earthquake, occurred at 14:28:01 China Standard Time on May 12, 2008. The earthquake's epicentre was located 80 km westnorthwest of Chengdu, the provincial capital, with a depth of 19 km. The earthquake ruptured the fault for over 240 km, with surface displacements of several meters. The earthquake was also felt in nearby countries and as far away as both Beijing and Shanghai— 1,500 and 1,700 km away, respectively—where office buildings swayed with the tremor. Why? The earthquake occurred as the result of motion on a northeast striking reverse fault or thrust fault on the north-western margin of the Sichuan Basin. The earthquake’s epicentre and focal-mechanism are consistent with it having occurred as the result of movement on the Longmen Shan Fault or a tectonically related fault. The earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against strong crust underlying the Sichuan Basin and southeastern China.

Izmit (Kocaeli), Turkey 1999 The Izmit earthquake occurred on 17th August in 1999 in north-western Turkey at 03:01 local time and lasted 37 seconds. The shock had a moment magnitude of 7.6.The earthquake occurs along the western region of the North Anatolian Fault Zone (NAFZ) . The Anatolian Plate which consists primarily of Turkey, is being pushed west around 2-2.5 cm a year, as its squeezed between the Eurasian plate to the North and the Arabian plate to the south. Major earthquakes in Turkey result mainly from slip along the NAFZ or the East Anatolian Fault. The depth of the focus was 15km (9.3 miles) making it a shallow earthquake. The Izmit earthquake had a rupture length of 150km extending from the city of Duzce all the way into the sea of Marmara along the gulf of Izmit. The earthquake’s epicentre was identified as being based between Izmit and Bursa, around 100 km east of Istanbul. The earthquake affected many areas in North-western Turkey including Golcuk, Derince, Darica and the large town of Adapazarı. Primary effects : ● Approximately 17,120 deaths and approximately 50,000 casualties ● 120,000 houses beyond repair / 20,000 buildings collapsed ● Extensive damage to several bridges and structures on the Trans-European Motorway including 20 viaducts, 5 tunnels and overpasses. Secondary effects: ● Disease e.g Cholera and Typhoid ● Earthquake caused a tsunami in the sea of Marmara that was around 2.5m high and killed around 155 people. ● The earthquake sparked a disastrous fire at the Tupras petroleum refinery

San Francisco, USA 1989 San Francisco is a city located in Northern California, on the West coast of the USA. The earthquake struck the Bay Area on 17th October 1989 at just after 5:00 pm local time and lasted approximately 15 seconds. It had a magnitude of 6.9 on the moment magnitude scale. The epicentre was in the Santa Cruz mountains, 60 miles south of San Francisco. It was triggered by a slip along the San Andreas Fault, which forms a tectonic boundary between the Pacific Plate and North American Plate. The southwestern motion of the North American Plate towards the Pacific Plate creates compressional forces along the eastern side of the fault. Tremors from the quake were reported 400 miles away in Los Angeles and 200 miles away in Reno, Nevada. Primary effects: ● 100,000 buildings were damaged. ● A 2 mile section of the Nimitz Freeway collapsed killing 42 people. ● A 20 m section of the Oakland Bay Bridge collapsed. ● Many homes were destroyed in the Santa Cruz mountains or threatened by ground movement. Secondary effects: ● Over 30 fires broke out due to burst pipelines. ● Landslides occurred on coastal cliffs along the San Mateo County coastline, killing one person. ● A rock avalanche from a cut slope on Highway 17 west in the Santa Cruz mountains. Debris were still falling two days later. ● 12,000 people were made homeless.

Kobe, Japan Location Kobe is located in the southeast of Japan and is a megacity, which is found on a fault line. The earthquake hit Kobe on 17th January 1995 at 5.46am and lasted about 20 seconds. At this plate margin, the Pacific plate was pushed under the Eurasian plate (subduction zone), so stress built up and was released, causing the earthquake. This is also known as an eastwest strike-slip fault where the Eurasian and Philippine plates interact. The focus was only 16 km below the crust and measured 7.2 on the Richter scale (6.9 on MMS). Its epicentre was the northern part of Awaji Island in the Inland Sea, 20 km off the coast of Kobe. Primary effects ● 200,000 buildings collapsed and 1km of the Hanshin Expressway and many other bridges collapsed and many highways were elevated ● 120 of 150 quays in the port of Kobe were destroyed and the port itself was damaged ● Even earthquake buildings swayed and the ground beneath was unstable ● Over 6,430 people died and 35,000 were injured ● Over 104,000 houses were destroyed and 450,000 left damaged Secondary effects ● Over 250,000 people left homeless and had to live in temporary shelters

● Electricity, gas and water supplies were disrupted and fires broke out, damaging 7,500 houses ● Roads were at gridlock, delaying ambulances and fire engines ● 716 aftershocks (74 could be felt by humans) - people were afraid to return home ● Industries e.g. Mitsubishi and Panasonic were forced to close Haiti, 2010 Haiti is a part of a large Caribbean Island called Hispaniola which is shared with the Dominican Republic to its east. Port Au Prince is on a fault line off the Puerto Rico Trench where the North American Plate is subducted under the Caribbean plate. This is a strike slip fault as the Caribbean Plate south of the fault line was sliding east and the smaller Gonave Platelet north of the fault was sliding west. This caused the earthquake on 12 January 2010 whose epicentre was 10 miles southwest of Port Au Prince. It had a shallow focus of 5 miles below the surface and measured 7.0 on the Richter scale. Primary effects ● 316,000 people were killed and 1.3 million people were made homeless. 3 million people were affected by the earthquake ● 250,000 homes and 30,000 other buildings, including the President’s Palace and 60% of government buildings, were either destroyed or badly damaged ● Transport and communication links were also badly damaged by the earthquake ● Hospitals (50+) and schools (1,300+) were badly damaged, as was the airport’s control tower ● The main prison was destroyed, and 4,000 inmates escaped Secondary effects ● 1 in 5 people lost their jobs because so many buildings were destroyed. Haiti’s largest industry, clothing was one of the worst affected ● The large number of deaths meant that hospitals and morgues became full and bodies then had to be piled up on the streets ● The large number of bodies meant that diseases, especially cholera, became a serious problem in November ● 2 million people were left without food and water ● It was difficult getting aid into the area because of issues at the airport and generally poor management of the situation ● People were squashed into shanty towns or onto the streets because their homes had been destroyed leading to poor sanitation and health and looting became a real problem...