Download earthquakes

EARTHQUAKES AND
EARTH’S INTERIOR
EARTHQUAKES
• Definition
• vibration of Earth’s surface caused by
energy released from rocks breaking
under stress or by friction between
moving rock materials at or below the
Earth’s surface
Global Earthquake Distribution
EARTHQUAKES
Terms
• focus
• exact place of origin of earthquake
disturbance and with few exceptions
is located below surface of the Earth
• epicenter
• is the position on the surface of the
Earth directly above the focus
Earthquake Focus and Epicenter
EARTHQUAKES
• aftershock
• an earthquake generated at or near the
focus following the main shock
• may be of substantial magnitude but
smaller than main shock
EARTHQUAKES
• tsunami
• a seismic sea wave generated by an
earthquake with an epicenter above the
ocean crust or near the ocean
• seismic sea waves can be disastrous to
property and life near ocean areas
• the Good Friday Earthquake of 1964 in
Alaska generated a tsunami which
devastated the west coast of North
America
Tsunami in Pacific Ocean
EARTHQUAKES
• earthquake intensity
• is a measure of the effects or physical
destruction caused by an earthquake
• earthquake magnitude
• is a measure of the strength of or
energy released by an earthquake
EARTHQUAKES
• Factors influencing the intensity of an
earthquake
1. total energy released at focus
2. distance of focus to the surface
3. type of rock support in an area
• solid bedrock will inhibit large
damage
• thick soils will settle and damage
results will be greater (Liquidfication)
4. building construction and popul.
density
EARTHQUAKES
• Earthquake magnitude
• Measured by the Richter scale
EARTHQUAKES
• Pacific Ring Region (Ring of Fire)
• is a region with many plate boundaries
especially convergent types
• about 80% of the earth’s earthquakes
EARTHQUAKES
• Mediterranean region
• large concentrated area of plates and
about 15% of earth’s earthquakes
• Ocean ridge areas and intracontinental
areas
Global Earthquake Distribution
List the effects of a
major earthquake.