lesson 5.2 Flashcards
He is often referred to as the Father of Modern Geology.
He believed that Earth is continuously formed
He explained the features of the Earth’s crust through his theory of
uniformitarianism.
James Hutton
what is an earthquake
a sudden movement of the ground that
releases elastic energy stored in rocks and
generates seismic waves.
The initial movement that causes seismic
vibrations occurs when two sides of a fault
suddenly slide pasty each other, generating
an
earthquake.
Are the natural phenomena that might
impact an area or a region.
Are measured in terms of energy and
strength of the shaking, etc.
hazards
Refers to anything that could potentially lost when the
hazard occurs.
Can be measured in fatalities or amount of damage.
risk
Earthquake hazards are
classified into:
primary earthquake hazard
secondary earthquake hazard
they are the direct result
of the movement of the
ground.
primary earthquake hazard
primary earthquake hazards includes:
ground shaking
landslides
liquefaction
surface rupture
Can be seen as a hazard created by earthquake, or a trigger for other hazards.
described the vibration of the ground shaking when an earthquake occurs, usually recorded in terms of intensity.
ground shaking
If the ground is saturated with water, the shaking will result in more ———
landslides
include a wide range of ground movement such as a rock fall, rock slide, debris slide, and shallow debris flow
landslides
A magnitude ——— earthquake is strong enough to trigger rock falls.
-4.0
occurs when sand or soil and groundwater are mixed during the shaking of a moderate or strong earthquake. which results in the ground becoming soft, exhibiting properties similar that of a quicksand.
liquefaction
Highly susceptible to liquefaction:
Floodplains
sand bars
Abandoned river channels
Coastal areas
Swamps
Marshes
River deltas
Reclaimed lands.
When the earthquake occurs, ground rupture happens at the area where the fault zone moves.
surface rupture
Surface rupture is not a single line with a fixed width, but a zone with variable width where the
fractures have developed, these are called ———-
deformation zones
Geologist from PHIVOLCS found a surface rupture that is a part of the reverse fault called —————, which is about 6km long.
North
Bohol Fault
Are the results of the primary
hazards, which can prove to be
more catastrophic.
secondary earthquake hazards
secondary earthquake hazards includes
tsunamis
seiche
flooding
fire
a huge wave caused by an earthquake that originates from under the ocean .
also generated by landslides, underwater volcanic eruptions, or an asteroid hitting the ocean.
tsunamis
two types of tsunamis:
locally generated tsunami
far-field tsunami
are caused by earthquakes from nearby trenches.
locally generated tsunamis
are generated by earthquakes from sources that are located farther from the impact.
far-field tsunamis
are almost unnoticeable, and it can reach
up to 970 km/hr.
tsunamis
The type of rock or soil also affect the ———– of an
earthquake
magnitude
Areas with ———– can experience very strong shaking even if it is far from the epicenter.
soft soil
seek higher ground, you must be at least ———– above sea level
30m
The key formation for ——– formation is that the body of water must be
partially bounded, allowing formation of the standing wave.
seiche
Apart from continuous rain, flood can also :
When a tsunami hits land, when the water that remains can flood the coastal areas.
Landslide that hits a river, can cause the water to swell and pour out on the areas beside the river.
flooding
A myriad of possible sources of ignition have become available,
such as gas lines, electrical and other utility wires.
fire
