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28 Cards in this Set
- Front
- Back
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When was the Kobe earthquake in Japan?
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1995
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How many people died in the Kobe earthquake?
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5000
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Kobe earthquake
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- Kobe is more densely populated-multi-storey buildings collapsed easily in the earthquake
- The Kobe earthquake struck early in the morning when many were asleep. - In Kobe, fires broke out, killing many, and they were hard to control |
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What factors affect the rate of flooding?
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- Drainage- if there are a lot of tributaries, water will be collected efficiently and possibly cause flooding
- Heavy rainfall- unable to infiltrate ground so collects on surface - Geology (rock type)- rocks like clay do not allow water through, whereas permeable rocks like limestone do - Angle of slope- slopes cause water to flow off the surface, whereas flat land allows water to collect - Previous weather- Previous rainfall could waterlog the ground and extreme heat or icy conditions can cause an impermeable surface - Human interference- buildings/tarmac create an impermeable surface |
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What is the DISCHARGE of a river?
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The given amount of water in a river, at a given point in time
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What is a flood?
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A flood occurs when a river overflows its banks-exceeds its bankfull discharge.
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Where is Boscastle?
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North Cornwall coast, previously a fishing village but now 90% of the economy is reliant on tourism.
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When did the Boscastle flood take place?
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16th August 2004
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Why did the Boscastle flood occur?
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- Two rivers meet-the Valency and the Jordan
- Close to the sea-heavy rainfall - Lack of vegetation on the slopes - Steep land and hills - The bridge acted as a dam - Boscastle's valley catchment area extends 9 square miles spanning inland onto Bodmin Moor, with steep-sided valleys and 'flashy' tributaries - More 1400 millions litres of rain fell in just 2 hours on the afternoon of the 16th |
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What were the impacts of the Boscastle flood?
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- Largest peacetime rescue in Britain
- 58 properties flooded and 4 demolished (including the Visitor Centre) - Costs-£2 million - 100 people airlifted to safety - 84 cars wrecked and 32 washed away - 4 footbridges on the Valency were washed away |
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How has Boscastle been managed since the flood?
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- Landuse zoning-low value car parks in high risk area
- Flood warning system planned - New culvert on the River Jordan, extending 80m into the Valency - Reducing global warming/greenhouse gas emissions - Environmental Agency-flood prevention |
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What is the structure of the Earth?
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The earth consists of four concentric layers: inner core, outer core, mantle and crust.
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Why do plates move?
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- Tectonic plates are constantly moving
- The plates 'float' on the mantle, generally moving just a few cm a year - This movement is caused by convection currents generated by the hot temperatures within the Earth - The source of heat for convection currents is radioactive decay deep within the Earth |
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How do convection currents work?
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- Convection currents are formed when a liquid (in this case magma) is heated ang begins to rise
- As it gets nearer the Earth's surface it cools and sinks back down to the bottom of the mantle, where it is heated again-creating a convection current - The plates that rest on top of the mantle move a few cm a year due to the movement of magma in the mantle, caused by convection currents |
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What are plate margins?
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Plate margins are the places where tectonic plates meet-these are areas of great crustal stress and activity due to the movement of the plates.
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What are the 4 types of plate boundary?
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1. Destructive margins
2.Collision zones 2. Constructive margins 3. Conservative margins |
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What is an earthquake?
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The sidden shaking or trembling of the Earth's crust, caused by a sudden release of tectonic strain-as plates try to move, pressure builds up under the rocks, and eventually ruptures causing an earthquake.
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What are the features of an earthquake?
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- Usually occur on plate boundaries of along fault lines, although they can be triggered by human activities such as mining
- Shakin/trembling of the ground - Shock waves caused by sudden movement - The vibrations which occur during an earthquake, are usually sent out as seismic waves, and can be detected by a seismograph - The source of an earthquake is called the focus-earthquakes with a focus close to the surface are most damaging - The epicentre, is the point on the Earth's surface, directly above the focus-the epicentre of an earthquake is affected first and suffers the most damage - Earthquakes sometimes cause tsunamis |
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What is the Richter scale?
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- It measures the size of earthquakes
- The Richter magnitude test scale designates a single number to represent the size of an earthquake - It measures from 1-10 positively and negatively and is assigned by calulating the horizontal amplitude from zero on a seismometer |
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When did the Kobe earthquake erupt?
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17th January 1995
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What time did the earthquake strike Kobe?
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5.45 am
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Where did the earthquake strike?
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- South Japan (Pacific Ocean)
- 14km beneath the northern part of Awaki Island in Osaka Bay - Epicentre close to Kobe, Kyoto and Osaka |
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What did the Kobe earthquake register on the Richter scale?
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7.2
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How long did the earthquake last?
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20 seconds
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What caused the Kobe earthquake?
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- Kobe lies on the Nojima fault
- Destructive plate margin - The heavier oceanic Phillippine plate is forced under the lighter continental Eurasian plate - The sudden movement of the plates caused an earthquake |
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What were the short term effects of the Kobe earthquake?
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- Nearly 6500 dead
- 35,000 injured - Over 300,000 people evacuated - Nearly 175,000 houses collapsed - 3 hospitals ruined - 35 schools destroyed - More than 275,000 communication lines down - More than 300,000 homeless - Water, gas, and electricity interrupted - Transport network wrecked - Nearly 200 berths at Kobe and Ashiya damaged - More than 600 aftershocks felt worldwide by 8pm that evening |
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What were the long term effects of the Kobe earthquake?
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- 10 billion yen in damage (£43 million)
- Population fell by 33,000 - More than 5500 buildings destroyed by fire needed rebuilding - Businesses closed - Bridge connecting Port Island to the mainland came down - Jobs created to rebuild the city |
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How is the earthquake risk in Kobe being managed?
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- Injecting liquid into faults
- Rolling weights on roofs - Shutters on windows - Reinforced foundations - Rubber shock absorbers - Motion instruments installed - Rescue drills practised - Education-signs, leaflets, lessons in school - Earthquake Memorial Park - Open areas for pedestrian evacuation - Residential Earthquake Insurance Scheme - Funding levels increased - Research programmes into seismology, earthquake engineering and disaster management - Research project to map active faults |
