plate tectonics

plate tectonics

1. mt Etna MEDC 1991-93

   • on the island of sicili. 3323 m tall towers over catania the second largest city in sicily. the volcano has frequent small erruptions and lava flows but is not considered particularly dangerous. thousands of people work the fertile soil on the volcanos flanks. there are a number of small vents on which cinder cones have formedthe most promenent feature is the valle de bove which is a 10 km horse shoe shaped caldera (when a large explosion has blown the top of a volcano.) its open to the east. lava from the se flank has previously flowed into the sea. started to spill lava which flowwed down the valle del Bove towards the city of zafferana. to slow and stop the lava a ten meter high 400 meter long earth bank was built. at the end of the val del bove. held lava for about a year then it overflowed and quickly overcame a few small barriers bellow destroying some small buildings and orchards. large concreate bolders were droped into the primary  feeder lava vents to block it and eventually engeners managed to blow a hole in the lava tube, diverting the lava flow to an uninhabited area. 10 months later it stoped. the lava was viscous which is why this was possible. some argue the lave never would have reached zafferana as it had to travel 8 km beffor it was a threat but it may have done. also the erruption was 2300 m up its a strato volcano truncated by many small calderas . but in 2002 lava flow  compleatly destroyed a ski resort on the volcano and askh clouds severly effected  the city of catania.
   • lava was viscous and erruptio was 2300 m up
   • 3323 m tall
   • wall was 10 m tall and 400 m wide at end of valle del bove
   • towers over catania the second largest city in siccily
   • thousands of people work its fertile flanks
   • vale del bove a 1o km hores shoe caldera
   • had to travel 8 kn before serious threat.

2. the market rasen earthquake 2008 MEDC

   • 2008 Lincolnshire no buildings collapsed no one was killed like with all british earthquakes. Britain not near a plate margin so earthquake was caused by a build up of tension in the plates as they moved which was relised by movement within the plates ressulting in this earthquake.  One person was injured when a part of the chiminy fell through his roof and broke his pelvis. Many buildings had minor damage such as tiles sliding of roofs and damage to pavements through falling masonary.  insurance claims were setemated at a total of 30 million pounds. the strongest earthquake in britain for 25 years. magnitude 5.2 on the richter scale. shallow depth at 18km down. tremmors were felt 100 km away.
   • cost to insurance companies estimated at 30 million pounds
     • 5.2 on the Richter scale
     • Biggest earthquake in England for 25 years

3. Gujarat India 2001 LEDC

   • most powerfull to strike india in 100 years. shallow focus  17km. epicicenter near the small town of bhuj in gujurat. siesmic waves reascked into bangladesh, nepal and pakistan on the other side of the subcontinent. killing people. death toll was very difficult to calculate. communications with the outside word collapsed. many buildings were poorly built and even newly built buildings had little chance as they were made with cheep matirial. they were not designed to withstand earthquakes even though the area is know for siesmic activity. many small towns were obliterated. emergency servises had to be brought in from other places. much cultural palaces and temples, centuries old, destroyed. powerlines brought down , communications seerly disrupted. one of the most disasterous factors of the aftermath was the wide spread looting that took place. the scale was so large aurthoritys had little control. several hundred aftershocks followed, the highest was a magnitude of 5. rescue teams from all over the world were sent. britain sent a team of 69 sponsored by the department of international development. the death toll from disease (cholera and typhoid) spread by rotting bodies was greatly reduced by the spraying of disinfectant on boddies and collapsed buildings. also this was helped by water purification tablets. the indian government sent 500 trops and 40 military aircrafts and 3 navel vessels- two of which were floating hospitals hosting 200 patients each. some areas were so hard to reach that aid was brough in by air.
   • 7.9 on the Richter scale
   • between 20,000 and 30,000 people died.
   • over 1 million made homeless
   • over 345000 dwellings from flats to mud houses destryed
   • 90% of dwellings in budj were destroyed.
   • all four of budj's hospitals destroyed
   • Britain sent a team of 69 sponsored by the department of international development.
   • diarrhea and gastroentitis were however wide spread due to lack of sanitation.
   • the area is heavily dependent on agriculture so the loss of 20,000 cattle had an enoormous impact.
   • the overall cost was4-5 billion

4. Indian ocean tsunami 2004 LEDC

   • The epicenter was of the west coast of the indionisian island sumatra. earthquakes triggered as far as alaska.the indio-australian plate subducted beneath the eurasian plate, jolting the sea floor ten meters. a section of the eurasian plate rose several meters.  it occured 25km beneath the indian ocean. the 30 foot wave moved at 800km per hour. islands such as the maldives were effected as well as costal countries such as indionesia, thailand,malasia, india,sri lanka. no warning systems in the indian ocean. many tourists visiting in christmas holidays were also killed. whole towns were swept away. in sumatra over 1500 villages were destroyed. tourisem, infrastructure, communications, the economy, and transport damaged. the western side of  india did recive warning - eg kenya moved thousands of people to safty. warning systems have now been set up in the countries boardering the indian ocean.
   • magnitude 9
   • the earthquake lasted 8 minuets
   • 300,000 people were killed
   • 1500 villiges were destroyed in sumatra
   • many costal areas reliant on fishing and farming were damaged resulting in 100's of thousands of people unable to feed themselfs.
   • estimates insurance claims cost less than 5 billion.
   • over 14 billion dollars of humanitarian aid donated
   • the UN predicted that reconstruction would take at least 5 years.

5. japan tsunami 2011 MEDC

   • caused by larges earthquake in japan on record- 9 0n richter scale. 14 aftershocks magnitude 5. prepaired with warning systems and earthquake resistent buildings and disaster management plans.. but tsunami walls surrounding costal areas only 7 meters tall and tsunami was 10 m tall. struck 30 mins after the earthquake. had been predicted by warning systems 10 misn after earthquake so 20 min warning sent out . but many did not evacuate as desensitized by regular alarms and thought wall would be ok. 28 000 died.244000 refugees. caused melt down of nuclear power plants - multiple explosions and radioactivity relised to 10 km radius contaminating food water and people. estimated cost 309 billion dollars. devestated ne coast of japan. shortly aftyer the first shock wasve warning was automaticly issued to tv and mobile phones. defences gave people a false sense of security and therefore many died.
   • est cost 309 billion dollars
   • 130,000 buildings destroyed despite earthquake resistant designs.
   • fukoshima nuclea melt down many fleed the country in fear but it was ok. japan plan to faze nuclea out by 2040.

6. North ridge earthquake La 1994 MEDC

   • occured at four in the morning on a bank holiday - low death toll. many buildings with weak lowwere floors such asfirst floor parking collapsed, as did those with wooden structures. There already was legislation saying all hospitals and schoolshad to be earthquake resistent so many survived. new legislation was relised ensuring by 2005 all hospitals have earthquake proof acute care and emergency wards in california. Over 700,000 applications made for state financial help. 57 people died. 5.8 0n the richter scale. it ressulted from movement along a previously unknown thrust fault. shallow focus. highest ground shaking ever recorded in north America. 11 major roads required closure to rebuild. some were as far as 32km from the epicenter
   • 57 people died- 1500 seriously injured.
   • over 700,000 applications made to state financial help.
   • 11 thousand land slides were triggered and 22 hospitals were damaged.
   • over 20 thousand were immediatly made homeless
   • 600 aftershocks followed. one at a magnitude of 5.6 11 hours later.
   • 9000 premises without electricity
   • The Santa Monica freeway- one of the bussiest highways in USA took three months to repair.

7. Soufiere hills- Mont Serrat island 1995-97 LEDC

   • the soufireer hills volcano had been dormant for many centurys. Early activity incuded ash and steam explosions reaching 2500 meters up ito the atmoshere. numerous small earthquakes were also expirienced. in 1996 there was doam growth , huge ash clouds and small pyroclastic flows. small explosions and balistic projections began to take place. Then a huge eruption and giant pyroclastic flows. 4-5 million m3 of matirial erupted into the atmosphere. most went down the northern flank. people and houses destroyed. only 40 or the islands 100km 2 was considered safe to live on. 12 m of mud from lahars and ash burried the capital city plymouth. the airport and many docking facilitys were destroyed. Montserrat was still an overseas teritiory of the UK so the UK had to provide and assist by: setting up exclusio zones evacuating 7000 of the islands 11000 inhabitants to nighbouring islands such as antiga or uk. finacial help was given to help these people resettle. many  of the pop were resettled from the uninhabitable south to the safer north side where tempory shelter was set up. air and sea links reestablished. permenent housing built the capital became salem which is in a safer northern location. farming land was provided for the resettled people. montserat volcano observatory was set up. over 100 million pounds was spent on this stuff. five years on many inhabitents were still in tempory accomedation but many new homes had also been constructed. to aid redevelopment some of the tourrist industry was restored- at first few people wanted to visit but then came to see volcano. some of the reffugees from the uk were returned. the airport was rebuil in 2005. a port. fifa funded  a new football pitch. due to the warning signs of the volcan erupting evacuation started in 1995 so desth toll was low. the uk provided 14 million pounds in long term aid to develop the north. befor hand all the key infastructur was in the most high risk place and no disaster management plan had been arranged. it is a composite volcano- pyramid formed by layers of ash and lava. it is above the convergent destructive margin of the carabbean plate and  north american plate. 1 billion people lost thier homes. 2 thrirds of the homes on the island were destroyed by pyroclastic flow. vegetation and arrable land was destroyed but made fertile by the volcanic ash. 19 people died. there were riots in england as people argued the governement needed to give more relife aid.
   • 19 people died
   • 7000 of the islands 11000 inhabitants were evacuated- started 1995.
     • 2/3 of homes on the island destroyed.
   • the uk provided 14 million pounds of long term aid and 100 million in short term repairs
   • 4-5 million m3 of matirial relised in 20 minuets
   • only 40 of the islands 100 km were safe to inhabit
   • estimated 1 billion pounds of damage caused