sci 8 q2
SCIENCE 8 REVIEWER Q2
Earthquake- sudden shaking of the ground caused by the underground masses that suddenly shift in position.
Seismic waves- energy that is released outward in all directions in the form of spherical wave energy.
Seismology is the study of earthquakes and the waves they create. Scientists are called Seismologists.
Earthquakes occur on faults. A fault is a thin zone of crushed rock separating block of the earth’s crust. Faults can be horizontal, vertical or at some angle to the surface of the earth.
TYPE OF FAULTS:
1. Normal Fault- Pulling apart, has the divergent plate boundary, Foot wall above, hanging wall below. Type of stress; tensional stress. Produces valley (ies)
2. Reverse Fault- known as thrust fault, found in collision zones. Collides with eachother. Convergent plate boundary. Hanging wall above, foot wall below. Has compressional stress. Produces mountains
3. Strike-slip fault- sliding past one another. Has the Shear stress. Dextral (right handed) sinistral (left handed) has the transform boundary.
Epicenter- the point directly above the focus.
Focus- the origin of the earthquake.
Magnitude- measures the energy being released from the origin of the earthquake.
Intensity- strength of the trembling made by the earthquakes at a place.
Intensity is determined by the Mercalli scale.
Richter magnitude scale- measures the quantity of seismic energy released by earthquake.\
Active fault- generating earthquakes within 10,000 years. Shallow earthquakes occur on active faults.
Holocene active fault- 10,000 years
Late quaternary fault- 130,000
Quaternary fault- 1,600,00 years
Inactive faults- did not show any signs of generating earthquakes in the last 10,000 years,
Seismic wave- vibration generated by an earthquake, explosion, or similar energetic source which carries energy.
Seismogram- device that measures earthquakes an traces earthquakes throughout the earth.
A seismograph is a device that measures and records the vibrations caused by seismic waves from earthquakes, explosions, and other events that shake the Earth.
Refraction- an observable property of waves, when waves move from one medium to different medium.
BODY WAVES: interior
1. Primary waves-arrives first at seismic station, 5,2 km/s, travel in all states of matter. They push and pull the rocks as they move through just like the sound waves that push and pull the air.. also known as compressional or longitudinal waves
2. Secondary waves- can only travel in solid, 3.6 km/s, move rock particles up and down, or side-to-side perpendicular to the direction that the waves are traveling in. S waves are also known as transverse or shear waves
SURFACE WAVES: crust, causes the most damage
1. Love wave-This wave is the fastest surface wave and moves the ground from side-to-side. Love waves produce entirely horizontal motion. It can travel a velocity of 4 km/s and create more shaking.
2. Rayleigh Waves-rolls along the ground
3. Shadow zone- area where no direct P or S waves are detected.
TYPHOON
a tropical cyclone is a system of thunderstorms moving in a circular direction. Northwest direction, does NOT form in southeastern
Cyclone- south pacific
Hurricane- northeastern pacific
Typhoon- northwestern pacific
strong winds (squalls). The surface wind increases in magnitude and is maintained over a time interval of several minutes to half an hour.
Tornadoes. These are produced by tropical cyclone characterized by a violent and destructive whirling wind accompanied by a funnel-shaped cloud.
Rainfall and Flooding. Rainfall associated with tropical cyclone is both beneficial and harmful
Storm surge. This is an abnormal rise of water due to tropical cyclone and it is an oceanic event.
An emergency kit is a collection of basic items that a household should have in the event of an emergency like a typhoon
Landforms like tall mountain ranges act as an obstacle to traveling air masses, forcing them to rise over the peaks.
the windward side which has more vegetation compared on the leeward side. This is because of the amount of precipitation the windward side receives. When air goes up into the mountain, it loses its moisture and only dry air proceeds to the leeward side making that side produce less vegetation.
Typhoon gains energy from warm ocean water and loses it over cold water.
for a typhoon to develop, it needs the abundance of warm water, high humidity, optimal location, ocean water with a temperature of 26.5˚C, spanning from the surface up to the depth of at least 50 meters (160 ft), and low vertical wind shear
Accurate track prediction depends in the position and strength of high-and low-pressure areas, and on how those areas will migrate during the lifetime of a tropical system.
Comets, meteors, and asteroids vary in size and composition. Their ability to reflect light depends on their silicate content, which is a metal containing silicon, oxygen, and other metals. Asteroids with less silicate content are harder to detect. Comets and asteroids move slowly across the sky and can be observed for extended periods. Comets typically originate from the Oort Cloud or the Kuiper Belt, while asteroids come from the Asteroid Belt between Mars and Jupiter. The gravitational pull of Jupiter is thought to have affected the Asteroid Belt's formation.
Asteroids have a more circular orbit, while comets have elongated orbits. The composition of these celestial bodies differs as well; asteroids contain metals like iron and nickel, while comets are made of ice, dust, and metals like sodium and argon. Halley’s Comet, a short-period comet, orbits the Sun every 75–76 years, whereas long-period comets take much longer. Asteroids, with their rocky composition, provide insight into the chemical makeup of planets, and scientists believe an asteroid impact may have contributed to the extinction of the dinosaurs.
Meteoroids are fragments of asteroids or comets. When meteoroids enter Earth's atmosphere, they become meteors, and if they land on Earth, they are called meteorites. Meteor showers occur when Earth passes through debris left by comets or asteroids. The orbits of asteroids and comets differ, with asteroids having more circular orbits and comets having more elliptical ones.