They are common in california along the san andreas

They are common in California along the San
Andreas fault.
The best known strike-slip earthquake is the Loma
Prieta earthquake that disrupted the 1989 World
Series in Oakland, California.

Thrust Earthquakes
These earthquakes occur on faults that separate
converging plates.
They are also called subduction earthquakes.
They are common off the coast of B.C., Washington,
and Oregon.
These earthquakes are the strongest on Earth (some
are larger than M9) and can produce tsunamis.

Normal Fault Earthquakes
These earthquakes occur on faults associated with
divergent plate boundaries.
They are common along the Mid-Atlantic Ridge.
Most are located under oceans and are generally
smaller than M6. (Tsunamis need at least a M7)

Intraplate Earthquakes
Definition:
An earthquake on a fault in the interior of a
continent, far from a plate boundary.
These earthquakes are typically smaller than plate
boundary earthquakes.
However, damage could be considerable due to lack
of preparedness.

Intraplate Earthquakes
Because of dense continental bedrock, these
earthquakes are felt over large areas.
There are two relatively active intraplate zones in North
America: Central Mississippi River Valley and St.
Lawrence River Valley
The New Madrid earthquakes in Missouri (1811-12) were
over M7.5 and felt over the entire continent.
The recurrence interval in this area is likely several
hundred year.
RI: The time between consecutive events

Earthquake Hazard Map

Effects of
Earthquakes
Several different effects
related to earthquakes
contribute to deaths and
property destruction.
Primary effects: ground
shaking, surface rupture
Secondary effects:
liquefaction, land-level
change, landslides, fire,
tsunamis

Ground Rupture
Displacement along faults causes cracks in the
surface.
During strong earthquakes, fault scarps (photo) can
be produced that extend for hundreds of kilometres.
Figure 3.20

Ground Rupture
Ground rupture can uproot
trees, collapse buildings, and
destroy bridges, tunnels,
and pipelines.

Liquefaction
Definition:
The transformation of water-saturated sediment
from solid to liquid.
This may occur during strong earthquakes when
water pressure becomes high enough to suspend
particles of sediment within the soil.
Once the pressure decreases, the sediment
compacts and regains its strength.

Liquefaction
Watery sand and silt may flow upward along
fractures in the overlying solid material.
This effect can cause extensive damage.
Figure 3.22
Figure 3.24

Landslides
Ground motion produced by an earthquake can
cause rock and sediment to move downslope.
A single earthquake in a mountainous area can
cause thousands of landslides.

Fires
Ground shaking and rupture can sever power and
gas lines, starting fires.
Appliances may topple over causing gas leaks that
ignite. (Huge problem in urban areas)
80% of the damage during the 106 San Fran
earthquake was caused by fire. (Buildings fall,
firetrucks can’t get through the city)
The earthquake doesn’t necessarily cause the major
damage, it’s the SECONDARY EFFECTS.

Haiti Earthquake