Nature of Earthquake and Earthquake hazard Flashcards
Layers of the earth
Crust, Lithosphere, Asthenosphere, Mantle, Outer Core, Inner Core
Compositional Layers (chemical)
Crust, Mantle. Core
Mechanical Layers
Lithosphere, Asthenosphere, Mesosphere, Outer Core, and Inner core
Composition of Tectonic Plates
Crust (Gigantic and Basaltic Rocks), Lithosphere and Asthenosphere
proposes that the lithosphere is divided into a series of plates that fit together like the pieces of a jigsaw puzzle
Theory of tectonic plates
a weak to violent shaking of the
ground produced by the sudden
movement of rock materials below
the earth’s surface along plate
boundaries
Earthquake
How are earthquakes generated
Earthquakes are usually caused by sudden slippage along a fault line
who concluded the elastic rebound theory
Henry Fielding Reid
the earthquake must have been involved in a previous elastic stress
Elastic rebound theory
Two types of earthquakes
- Tectonic earthquakes
- Volcanic Earthquakes
Produced by sudden movement along faults and plate boundaries
Tectonic Earthquakes
Produced by movement of magma beneath volcanoes
Volcanic Earthquakes
Deformation on the ground that marks the intersection of the fault
with the earth’s surface
Ground Rupture
Recommended buffer zone against ground rupture
At least 5 meters from both sides
Disruptive up and down, and
sideways motion experienced
during an earthquake
Ground shaking
2 types of Seismic waves
Body and Surface
Two types of body waves
Primary and secondary waves
Two types of Surface waves
Love and Rayleigh waves
A seismic waves that travels along or parallel to the earth’s surface
Surface Waves
waves that can travel throughout the earth’s inner layer
Body Waves
travel faster, move in a push-pull pattern, travel through solids, liquids and gases, and cause less damage due to their smaller size.
Primary waves
travel slower, move in an up-and-down pattern, travel only through solids, and cause more damage due to their greater size.
Secondary waves
surface waves that move parallel to the Earth’s surface and perpendicular to the direction of wave propagation.
Love Waves
surface waves that move in an elliptical motion, producing both a vertical and horizontal component of motion in the direction of wave propagation
Rayleigh Waves
Proper engineering practice
Adherence to the National Structure code of the Philippines
Why does seismographs produce 3 different seismograms
It responds to P, S, and surface waves moving in all directions
Phenomenon in which a water saturated sandy layers of earth act like liquid due to pressure created by the earthquake
Liquefaction
Structure protection measures in
case of liquefaction
- Avoiding construction of structures on soil susceptible to liquefaction
- Adjusting the structure foundations to the type of soil susceptible to liquefaction
- Improving or replacing the soil susceptible to liquefaction before construction of structure
Failure of slope materials due to strong ground shaking
Earthquake induced landslide
Waves or series of waves caused by an earthquake under the sea
Tsunami
two types of tsunamis
Distance and Local
Natural Observations for local tsunami warning
- A strong earthquake
- Unusual sea conditions
- Rumbling sound of the approaching waves
Solution: Immediately move to higher grounds
