3.1.5.4 Seismic Hazards

Question 1

what is an earthquake

Answer 1

a primary hazard associated with a seismic event that cause the ground to shake and sometimes rupture along the fault

Question 2

what is the focus of an earthquake

Answer 2

the point within the crust where the pressure release occurs

Question 3

what cities are most at risk from seismic hazards and why

Answer 3

islamabad, istanbul, lima

bcs they are some of the most seismically active regions of the world and are densely populates

Question 4

what are earthquakes usually like at destructive margins

Answer 4

huge due to massive pressure buildup

Question 5

where do shallow focus earthquakes usually occur

Answer 5

collisional and conservative plate boundaries

Question 6

describe global distribution of earthquakes

Answer 6

90% occur at plate boundaries
high density along the eurasian/pacific boundary, south/east asia
south europe cluster
west side of south america

Question 7

what is the benioff zone

Answer 7

where earthquakes occur when oceanic crust subducts underneath continental crust

Question 8

how is intensity of an earthquake measured

Answer 8

Modified Mercalli scale - subjective, observational, scale between 1 and 12

Question 9

how is the magnitude of an earthquake measured

Answer 9

richter scale - logarithmic, use seismometer