Tectonic Hazards

Question 1

3 main hazards of plate boundaries

Answer 1

Earthquakes, volcanoes, tsunamis

Question 2

Primary hazard are cause by…

Answer 2

P,S, Love waves

P waves= first type of seismic wave to be detected by seismograph after EQ, move thru earth by compressing and expanding material in the direction of wave propagation- less shaking but r 1st indication of EQ’sarrival

S= second seismic wave detected, move perpendicular to the direction of wave propagation , slower but caus more damage due to larger amplitude and complex motion

L= most destructive, move horizontally causing the ground to make side to side

Question 3

What are the primary hazards of tectonic activity

Answer 3

Ground shaking = most immediate and widely felt effect of an EQ
The intensity and duration of ground shaking determines the extent of damage. For example, the more intense the EQ and bugger magnitude on moment magnitude scale, the stronger the shaking which can lead to more damage e.g. infrastructure damage

Crustal fracturing= breaking and displacement of the earth’s crust along fault lines during an EQ which occurs due to accurate stress from tectonic activity exceeds the strength of rocks e.g. 1906 San Francisco EQ caused sig surface rupture along the San Andreas fault;t w displacement visible in the landscape

Question 4

What are the secondary impacts of tectonic activity.

Answer 4

Liquefaction=moving of land can force the water or air gaps in the rock out, causing the subsidence of land.
Effects= structures built on liquefied soil may sink or tilt causing foundations to fail, leading to severe structural damage or collapse

E.g, tohoku EQ 2011, caused widespread liquefaction , in areas w reclaimed land and loose sediments causing significant building damage and ground displacement