Earthquakes Flashcards
How do earthquakes form?
They occur at plate margins (e.g. conservative)
As the plates move past each other, the movement is not smooth. Plates sometimes lock causing a build up of pressure. This pressire is suddenly released in a jerkey movement in form of seismic waves. This release of pressure is calles earthwuake
Earthquake meaning
Shaking and vibration of ground caused by mvts of esrth’s crust
Focus
Point under ground that shock waves travel out from
Epicentre
Point on the ground above the focus where vibrations are felt the strongest
Richter scale
Scale to describe magnitude of earthquake
Seismogrqph
An instrument that measures shaking of ground to give strength of quake. Records vibrations on seismogram
Richter scale vs Mercalli scale
Richter: measures energy released by earthquake
Mercalli: measures effects cuased by earthquake
Richter scale tool: seismograph
Mercalli scale tool: observation
Richter scale scale: from 2.0 to 10.0 (never felt). A 3.0 is ten times stronger 2.0. Highest is 9.5 in chile
Mercalli scale scale: I(not felt) to XII (near total destruction)
Haiti earthwuake facts
Year: 2010
Magnitude: 7.0
Capital: Port au Prince
Plate boundary: conservative plate boundary
Plates: north american and csribbean plates
Deaths: 316, 000
Homeless: 1.5 million
Qhy was the earthquake bad?
People had no education on how to build houses, they were living in slum conditions, buildings were destriyed easily
Gov. Kept money for themselves and was corrupt, could have provided water and health care
Didn’t get any help from UN or other govs and charities, UN contaminated only source of clean water
Distance from epicentre
If the epicentre is in a city, lots of destruction. If it is in a desert nothing is affected
Quality of infrastructure
Better quality buildings cause less destruction and so less deaths. It will also cost less money if buildings don’t get destroyed.
Time of day
At night, people are in their own homes and know where it is safe to go. If it is rush hour everyone is outside and they are crammed together in some cases. More will get killed at day time
Time of year
During hot periods, secondary impacts are worse. Diseases spread more easily, heat stroke. In cold, pneumonia, frostbite. Kill more
Level of education
Higher level of education leads to less deaths because people know what to do. They know where to go, how to protect themselves. More will die if not
How to reduce death toll
Dome roofs, foundations which are solid but the building moves, building is solid but foundation moves, shatter proof glass, computer controlled weight on roof to reduce movement, furniture nailed down etc
Alarms in cities to warn against an earthquake to give time to evacuate
People educated to know what to do
Prediction systems to predict when an earthquake will happen to give time to evacuate
