Earthquake Hazards Flashcards
What are the three types of seismic wave?
Primary, Secondary, Love
What does the Mercalli Scale record?
The intensity and the effects of an earthquake
What scale does the Mercalli Scale use?
12 values in Roman numerals from I (hardly felt) to XII (total destruction)
What does the Moment Magnitude Scale record?
An earthquakes magnitude based on its seismic moment
What scale does the Moment Magnitude Scale use?
10 values (1 being lowest and 10 highest). An increase of one number means the quakes magnitude is 10x greater than the number prior
What are five factors affecting the Mercalli Scale?
Earthquake size, Depth of focus, Distance from epicentre, Ground conditions, Building quality
Define Isoseismal Lines
Lines connecting points on the earth’s surface at which earthquake intensity is the same/areas of equal intensity of damage
What are five effects of an earthquake?
Ground shaking, Liquefaction, Landslides, Seiche, Tsunami
Define Hazard
Something that can cause bodily harm
Define Risk
Chance of something happening and causing harm
What are seven factors affecting the risk of damage to property and loss of life?
Population density, Building design and density, Distance from epicentre, Level of development, Ground conditions, Coastal location, Magnitude
Define Earthquake Precursor
A wide variety of physical phenomena that reportedly precede at least some earthquakes
What are seven examples of earthquake precursors?
Groundwater level, Radon emissions, P-wave velocity, Electrical resistivity, Seismic gap theory, Earthquake lights, Animal behaviour
Define Seismic Gap
Where there has been less than expected movement (earthquakes) compared to other areas along the same fault
Define Geohazard
A geological condition that is dangerous (or potentially dangerous) to the environment and the people who live in it
