DRRR|WEEK 6 Flashcards
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
EFFECTS OF LIQUEFACTION
As a result, any heavy load on top of the sediment body will either sink or tilt as the sediment could no longer hold the load.
Happens when objects sink or fall to the bottom caused by an earthquake.
EARTHQUAKE-INDUCED GROUND SUBSIDENCE
EFFECTS OF EARTHQUAKE-INDUCED GROUND SUBSIDENCE
Ground subsidence can affect the stability of pipelines, drains, and well casings.
It can also cause the formation of ponds and cracks in the ground and, if the site is close to a populated area, can lead to instability of buildings
Series of waves commonly generated by under-the-sea earthquakes.
TSUNAMI
EFFECTS OF TSUNAMI
In addition to loss of life and mass injuries
Include damage to and destruction of homes and businesses, ports and harbors, cultural resources, utilities, and critical infrastructure and facilities.
There may be loss of access to basic services such as power, sewer,and water.
When masses of rock and other earth’s materials move downslope due to intense ground shaking.
EARTHQUAKE-INDUCED LANDSLIDE
EFFECTS OF EARTHQUAKE-INDUCED LANDSLIDE
Loose thin soil covering on the slopes of steep mountains are prone to mass movement, especially when shaken during an earthquake.
Many landslides occur as a result of strong ground shaking such as those observed on the mountainsides.
During earthquakes, Copp argues furniture creates empty spaces beside them due to their crushed remains acting like a roof. He calls these spaces ______
The larger and stronger the object, the less it will compact; the less it compacts, the larger the void next to it will be.
TRIANGLE OF LIFE
is a Japanese word meaning “harbor waves”.
A tsunami is commonly generated by disturbances associated with earthquakes occurring below or near the ocean floor.
It occurs when the earthquake is shallow-seated and strong enough to displace parts of the seabed and disturb the mass of water over it.
In addition, underwater volcanic eruptions and landslides can also generate a tsunami.
TSUNAMI
The increase in wave heights associated with or during typhoons (when there are strong winds) or tropical cyclones are called
Storm surges
TWO KINDS OF TSUNAMI
LOCAL TSUNAMI
FAR FIELD OR DISTANT TSUNAMIS
Are confined to coasts within a hundred kilometers of the source, usually earthquakes and a landslide or a pyroclastic flow.
It can reach the shoreline within 2 to 5 minutes.
LOCAL TSUNAMI
Can travel from 1 to 24 hours before reaching the coast of the nearby countries.
FAR FIELD OR DISTANT TSUNAMIS
SAFETY TIPS ON TSUNAMI
Use your common sense.
Keep a store of emergency supplies that include sufficient medications, water, and other essentials sufficient for at least 72 hours or 3 days.
Stay away from the beach and ocean.
Evacuate the area and go to high ground immediately.
Vessels should not return to port if they are at sea.
Listen to the radio or television for additional information.
Stay out of danger until you hear it is safe.
WHAT TO DO(3)
PREPAREDNESS & MITIGATION
RESPONSE
REHABILITATION
Conduct school advocacy on tsunami awareness, preparedness and mitigation.
Regular tsunami drills should be conducted.
Turn your radio and other communication devices to know if there is a tsunami warning if an earthquake occurs and if you are in a coastal area.
Assign a focal person to monitor and observe the water recession after an earthquake.
Be aware of the tsunami facts. This knowledge could save your life. Share your knowledge with your friends. It could save their lives.
If you are in school and hear there is a tsunami warning, you should follow the advice of teachers and other school personnel.
PREPAREDNESS & MITIGATION
CAUTION: Move away from the beach immediately, if there is noticeable recession in water away from the shoreline.
Move inland to predetermined higher ground immediately and stay there
Stay away from the beach, never go down to the beach to watch a tsunami coming.
High multistory reinforced concrete school building are located in some low-lying coastal areas
Small school buildings located at low-lying coastal areas are not designed to withstand tsunami impacts. Do not stay in these structures should there be tsunami warning.
Offshore reefs and shallow areas may help break the force of tsunami waves, but large and dangerous waves can still be a threat to coastal residents in these areas.
Staying away from all low-lying areas is the safest advice when there is a tsunami warning.
RESPONSE
Stay away from flooded and damaged areas until officials say it is safe to return.
Stay away from debris in the water; it may pose a safety hazard to boats and people.
Save yourself, not your possessions.
REHABILITATION
NATURAL SIGNS AN IMPENDING TSUNAMI
Occurrence of earthquake.
An unusually receding ocean or drawdown.
A series of surges that are five minutes to an hour apart.
