Science; Chapter 1 (Earthquakes and Faults) Flashcards
These are fractures or zones of fractures between two blocks of rock
Fault
May range in length from a few millimeters to thousands of kilometers
Fault
______ allow the blocks to move relative to each other
Faults
This movement may occur rapidly, in the form of an earthquake, or may occur slowly, in the form of creep
Fault
It is a small offset of the ground surface in which one side of a fault has shifted vertically in relation to the other
Fault Scarp
Relating to earthquakes or other vibrations of the Earth and it’s crust
Seismic
What are the layers of the Earth
-Crust, mantle, core
This natural disaster occurs when two blocks of the Earth suddenly slip past one another
Earthquake
These are giant waves caused by earthquakes or volcanic eruptions under the sea
Tsunamis
What are the three basic types of faults?
Normal fault, Reverse fault, Strike-slip fault
This is a type of fault in which the hanging wall moves down relative to the footwall as a result of extension
Normal faults
These are the most common type of faults
Normal fault
These are two blocks of crust layer pulling apart, extending the crust into a valley, thus creating a space
Normal fault
It is also called as Thrust fault
Reverse fault
A fault in which the hanging wall moves up relative to the footwall as a result of compression
Reverse fault
-In this fault, one block of crust slides on top of another
-These type of faults are normally found in collision zones where tectonic plates push up mountain ranges, for example, the Himalayas and Rocky Mountains
Reverse fault
A fault in which two blocks of crust slide past each other on the same plane. The motion experienced is right or left lateral instead of up and down
Strike-slip fault
These are faults that are rocks sliding past one another on a horizontal plane, with little to no vertical movement
Strike-slip fault
Examples of these types of faults are the San Andreas fault and the Anatolian fault
Strike-slip fault
This is a theory in which Earth’s crust and its rigid upper mantle are broken into enormous slabs called plates
Theory of Plate Tectonics
These plates are all moving in different directions at different speeds
Theory of Plate Tectonics
A theory where adjacent plates can collide and crash together, pull apart, or even side swipe each other
Theory of Plate Tectonics
The place where two plates meet is called a plate boundary
Theory of Plate Tectonics
Boundaries have different names, depending on how two plates are moving relative to each other
Theory of Plate Tectonics
These are the three types of Plate Boundaries
Divergent, convergent, transform boundaries
Are plates that move apart
Divergent boundaries
Is a feature that exists when two tectonic plates move away from each other
Divergent boundaries
Is a block usually found above the fault plane
Hanging wall
Is a block usually found under the fault plane
Foot wall
It is the result of these boundaries is a valley-like rift
Divergent boundaries
What are the three types of crust formation?
Continental to continental, continental to oceanic, oceanic to oceanic
What does continental to continental crust form?
Mountain/mountain ranges
What does continental to oceanic crust form?
Volcanoes
What does oceanic to oceanic crust form?
Islands, or island arcs
It is the process in which one tectonic plates submerges of falls under another tectonic plate
Subduction
It is where plates move toward each other
Convergent boundaries
Ranges from;
-Micro (1.0 - 2.9)
-Minor (3.0 - 3.9)
-Light (4.0 - 4.9)
-Moderate (5.0 - 5.9)
-Strong (6.0 - 6.9)
-Major (7.0 - 7.9)
-Great (8.0 and higher)
Magnitude
Earthquakes and volcanoes are more commonly experienced and found near these boundaries
Convergent boundaries
A boundary in which one of the plates descends beneath the other; this process is called subduction
Convergent boundaries
It is the seismic scale used to measure the intensity of an earthquake
PHILVOCS Earthquake Intensity Scale (PEIS)
This type of boundary is formed when two plates slide past each other horizontally
Transform boundaries
I - Scarcely perceptible
II - Slightly felt
III - Weak
IV - Moderately strong
V - Strong
VI - Very Strong
VII - Desructive
VIII - Very destructive
IX - Devastating
X - Completely devastating
PHILVOCS Earthquake Intensity Scale (PEIS)
It is a boundary where plates slide sideways past each other
Transform boundaries
(a) Why do earthquakes occur?
Plate boundaries are made up of many systems of fractures called faults
(b) Why do earthquakes occur?
The rough edges may cause the plates to rupture
There are more than a _______ earthquakes that occur in the planet each year; we just don’t feel most of them because they cause little disturbance on the surface
million
It is used to detect earthquakes at great distances
Seismometers or Seismograph
This is where the earthquake originated
Focus or Hypocenter
Located directly above the focus
Epicenter
It is the so called “GPS” of the earthquake
Epicenter
It is the study of earthquakes
Seismology
Good To Know!
On 17 August 1976, the Philippines experienced a 9-meter high tsunami caused by the 7.9-magnitude earthquake at the Moro Gulf. The 9-meter high tsunami destroyed crops, infrastructures, and other properties, and brought about thousands of casualties. The 1976 Moro Golf tsunami is one of the worst tsunamis experienced in the Philippines.
Instrument that records seismic waves
Seismometers of Seismograph
Simpler description of how Tsunamis form
- An earthquake rocks the ocean floor
- It displaces a volume of water, pushing it up
- This sets off an oscillation, which develop unerwater at great speed
- Sea water is sucked back from shore
- Waves get bigger as water gets shallower
What to do before an earthquake?
- The key to effective disaster prevention is planning.
• Know the earthquake hazards in your area.
• Follow structural design and engineering practices when constructing a house or building.
• Evaluate structural soundness of the buildings and houses; strengthen or retrofit them, if necessary. - Prepare your home, workplace, and school.
• Strap or bolt heavy furniture or cabinets to the walls.
• Check the stability of hanging objects such as ceiling fans and chandeliers.
• Store breakable items, harmful chemicals, and flammable materials in the lowermost secured shelves.
• Always turn off the gas tanks when not in use. - Familiarize yourself with the exit routes and places where fire extinguishers, first aid kits, alarms, and communication facilities are located. Learn how to use them beforehand.
- Prepare a handy emergency supply kit with first aid kit, canned food and can opener, water, clothing, blanket, battery-operated radio, flashlights, and extra batteries.
- Conduct and participate in regular earthquake drills.
What to do during an earthquake?
- Stay calm
- When you are inside a structurally sound building or home, stay there.
• Do the “duck, cover, and hold.”
• If possible, quickly open the door for exit.
• Duck under a sturdy desk or table and hold on to it, or protect your head with your arms.
• Stay away from glass windows, shelves, cabinets, and other heavy objects.
• Beware of falling objects. Be alert and keep your eyes open. - If you are outside, move to an open area.
• Stay away from trees, powerlines, posts, and concrete structures.
• Move away from steep slopes that may be affected by landslides.
• If you are near the shore and feel an earthquake, especially if it is too strong, move quickly to higher grounds or places. Tsunamis might occur after the earthquake. - If you are in a moving vehicle, stop and get out. Do not attempt to cross bridges, overpasses, or flyovers that may have been damaged
What to do after an earthquake?
- Be prepared for aftershocks. Once the shaking stops, take the fastest and safest way out of the building.
- Do not use the elevators.
- Do not enter damaged buildings.
- Do not use telephones unless necessary.
- Do not panic.
- Check if you have any injuries. If you have none, help other people with their injuries.
- Check water and electrical lines for damages.
- Check for spills of chemical, toxic, and flammable materials.
- Check and control fires that may spread.
- If you need to evacuate your residence, leave a message stating where you are going and bring your emergency supply kit.
- Keep updated on disaster prevention instructions from battery-operated radios.
It is a seismometer’s record of recorded earthquakes
Seismogram
It is a measure of the degree of an earthquake shaking at a given locale based on the amount of damage
Intensity
Estimates the amount of energy released at the source of the earthquake
Magnitude
Seismographs can also record;
Rockfalls, mine and quarry blasts. and nuclear explosions
