On 27 February 2008 an earthquake of 5.2 on the Richter scale hit Market Rasen in Lincolnshire. Little damage was done, but the event illustrates that hazards are an ever-present threat.
Grimsby and Doncaster were both flooded on 27 June 2007 during the ‘summer of floods’.
The Yorkshire Water area suffered a severe drought in 1995. High temperatures and low rainfall led to reservoir levels falling to 25% of capacity by August. Water was transported into the Yorkshire Water area by road tanker to increase supply, but at a cost of $47 million.
Flooding is a common hazard, both at the coast and along rivers.
Risk is related to both physical factors (e.g. heavy rain, impermeable rock/soil, sparse vegetation cover, steep slopes) and human factors (e.g. urbanisation, deforestation, poor river management, building on floodplains, lack of preparedness).
Flooding is possible in numerous locations (see map on next slide) and is likely to increase in frequency in many areas due to climate change.
Hydro-meteorological hazards: flooding (2) Global distribution of flood risk areas
The movement of the Earth’s tectonic plates is responsible for most earthquakes and volcanoes .
Oceanic plates are normally thicker and more dense than continental plates.
Most hazards occur at the boundaries where two plates meet.
The risk from these hazards is closely related to the type of plate boundary, with some boundaries more hazardous than others.
Plate tectonics (2) Plate margin Movement Earthquakes Volcanoes Destructive (oceanic–continental) Plates collide, the oceanic plate is subducted Very violent, up to 9.0 on the Richter scale Explosive and destructive Destructive (continental– continental) Plates collide creating a mountain belt Very violent, up to 8.0 on the Richter scale Very rare, but devastating Constructive (oceanic–oceanic) Plates move apart Minor, up to 5.0–6.0 on the Richter scale Effusive, non-violent Conservative (continental– continental) Plates slide past each other Very violent, up to 8.0 on the Richter scale None Mid-plate hotspots Plate moves over a zone of magma convection Minor, up to 5.0–6.0 on the Richter scale Effusive, non-violent
Disaster hotspots occur when two or more hazards occur in the same location.
In many cases, one hazard triggers or exacerbates another — earthquakes trigger landslides, and typhoon rainfall triggers lahars.
Disaster hotspots are the world’s most unpredictable and dangerous locations.
The Philippines and the California coast are compulsory case studies for this specification.
California and the Philippines compared (1) Earthquakes, volcanoes, landslides/lahars, typhoons, flooding Earthquakes, tsunamis, flash floods, fire Hazards Numerous volcanic islands Plains and mountain ranges Physical geography 40 per 1,000 7 per 1,000 Under 5 mortality rate 2.3% 0.7% Annual population growth 0.78 0.95 Human development index RIC MEDC/G8 Country type 1,415 45,000 Average income (US$) Philippines California coast