DRRR|WEEK 6 Flashcards
(43 cards)
Refers to a fracture, fissure or a zone of weakness where movement or displacement has occurred or may occur again
FAULT
is said to be “active fault” if it has historical and contemporary seismicity, has evidence of fault slip based on displaced rocks or soil units of known age and displaced landforms
A fault
is defined as a fault which has moved within the last 10,000 years
An active fault
is the vibration of Earth produced by the rapid release of energy within the lithosphere.
An earthquake
are caused by slippage along a break in the lithosphere, called a fault.
The energy released by an earthquake, travels in all directions from the focus in the form of seismic waves.
An earthquake
The movement that occurs along faults during earthquakes is a major factor in changing Earth’s surface.
Forces inside Earth slowly deform the rock that makes up Earth’s crust, causing rock to bend.
Elastic rebound is the tendency for the deformed rock along a fault to spring back after an earthquake.
An earthquake
is a device used to record the motion of the ground during an earthquake.
A seismograph
The rapid energy in the earth’s crust causes a shaking movement
An earthquake may be classified as either tectonic or volcanic.
In certain cases, earthquakes can result from man-made activities such as detonation of explosives, deep mining activities, etc. However, these earthquakes are mild and may be felt only as tremors.
EARTHQUAKE
This wavelike movement of the earth’s surface
SEISMIC WAVES
The source of the earthquake
Occurs under the ground and the waves are distributed to all directions from it.
FOCUS
The location on the surface of the earth directly above the focus
EPICENTER
The energy released produces an increasing distance from the focus.
The earthquake waves or vibrations reduce in intensity from the focus.
DISSIPATION OF ENERGY
Are a series of tremors that occur before the main earthquake.
Foreshocks
Are weaker earthquakes that follow the main shocks and can cause further damage to weakened buildings
Aftershocks
Refer to earthquake agents which have the potential to cause harm to vulnerable targets which can either be humans, animals or even your environment.
EARTHQUAKE HAZARDS
Permanent features an earthquake can bring out.
Examples
fault scarps, surface ruptures, and offsets of natural or human-constructed objects.
PRIMARY EFFECTS
happen when ground movement results in other types of destruction.
Examples
landslides, tsunami, liquefaction and fire.
SECONDARY EFFECTS
Various Potential Earthquake Related Hazards And Their Effects
-Ground Shaking
-Ground Rupture
-Liquefaction
-Earthquake-Induced Ground Subsidence
-Tsunami
-Earthquake-Induced Landslide
The disruptive up-down and sideways movement or motion experienced during an earthquake.
GROUND SHAKING
Strong ground shaking can cause objects to fall, break windows among others.
Strong ground shaking can also result in minor damages to buildings and worse, cause collapse of a structure.
Most part of the Philippines will experience shaking at different degrees depending on magnitude of earthquake
EFFECTS OF GROUND SHAKING
The movement of the ground along one side of a fault relative to the other side, caused by an earthquake.
The severity of the local effects depends on the complex combination of the earthquake magnitude, distance from the epicenter and the local geological and geomorphological conditions, which may amplify or reduce wave propagation.
The ground shaking is measured by ground acceleration.
GROUND RUPTURE
CAUSES OF GROUND RUPTURE
Sudden movement of one lithospheric plate past another
Stresses in the Earth’s crust, slippage
Earth-moving machinery
Local faults
EFFECTS OF GORUND RUPTURE
This will be experienced by areas where fault passes through
The movement may have vertical and horizontal component and may be as small as less than 0.5 meters to as big as 6 meters
When the ground soil is mixed with the groundwater, causing the soil to become less stable and lose its strength.
It is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading.
To understand liquefaction, it is important to recognize the conditions that exist in a soil deposit before an earthquake.
LIQUEFACTION