Global Hazards Flashcards
(19 cards)
What are the features of a tropical storm?
Tropical storms occur 5-30 degrees N/S of the equator and require a sea temperature of at least 27 degrees.
What are the different weather cells?
The different weather cells are Polar, Ferrel, and Hadley.
What causes El Niño?
El Niño occurs when sea temperatures reach 0.5 degrees above average due to ENSO, causing trade winds to reverse direction.
What are the effects of El Niño?
El Niño leads to warmer than average weather in the central and eastern Pacific, droughts in Australia, thunderstorms and floods in South America, and a rise in sea level of 30cm off the coast of Peru.
What causes La Niña?
La Niña occurs to counteract El Niño with stronger than usual easterly trade winds.
What are the effects of La Niña?
La Niña increases the risk of rainfall and flooding in Australia and brings cold water to the ocean from upwelling.
What are the features of a drought?
Droughts are extended periods of below average rainfall, often accompanied by high temperatures that evaporate water quickly.
What causes drought?
Droughts can be caused by changes in atmospheric circulation that reduce precipitation in an area.
What happened during the 2012 UK drought?
During the 2012 UK drought, taps still ran for water but hosepipe bans were implemented, dry moorland caught fire, and wine prices decreased due to an increased grape harvest.
What is a constructive plate boundary?
At a constructive plate boundary, plates move apart, forming new crust and creating land such as Iceland, resulting in earthquakes and volcanoes.
What is a destructive plate boundary?
At a destructive plate boundary, plates move towards each other, with the denser oceanic plate subducting under the continental plate, causing volcanoes and earthquakes.
What is a collision plate boundary?
At a collision plate boundary, two continental plates move towards each other, forming fold mountains like the Himalayas, and only earthquakes occur.
What is a conservative plate boundary?
At a conservative plate boundary, plates slide past each other at different speeds, resulting only in earthquakes.
What are earthquakes?
Earthquakes are sudden, violent shaking of the ground caused by a build-up of pressure from moving tectonic plates.
What are the features of an earthquake?
The focus is where the earthquake occurs, with depth affecting impact; the epicentre is the point directly above the focus on the surface, and seismic waves cause shaking.
What are composite volcanoes?
Composite volcanoes are tall, cone-shaped with explosive eruptions, formed on destructive plate boundaries from alternating layers of ash and lava.
What are shield volcanoes?
Shield volcanoes have gentle slopes, less explosive eruptions, and runny lava, forming on constructive plate boundaries or hot spots.
What are hotspots?
Hotspots occur when tectonic plates pass over a plume of magma, leading to a line of islands forming, such as Hawaii.
What is a case study related to earthquakes?
The 2015 Nepal Earthquake is a notable case study.
