science reviewer second quarter

A fracture or break in the Earth's crust where movement occurs during an earthquake.

• The release of stress along the fault causes the earthquake.

Types of Stress or Force

Tension when two plates move away from each other pulls and stretches rock

Compression when two plates are pushing toward each other squeezes rock causing it to fold or break

Shearing g when two blocks of rock are pushing in opposite directions sliding motion causes rock to break or change shape

4. Seismic Waves- these are waves that transfer energy from the focus. It has Two

types: Body waves and Surface waves.

Body Waves: Travel through the Earth's interior.

2 types of Body Waves

1. P-Waves (Primary Waves): Fastest, compress and expand like a slinky. Moving parallel to the direction of wave propagation. Travel through solids, liquids, and gases.

2. S-Waves (Secondary Waves): Slower than P-waves, move

perpendicular to the direction of wave propagation. Travel only through solids.

•

Surface Waves: Travel along the Earth's surface and cause most damage. Appear in a seismograph after P and S-waves.

2 Types of Surface Waves

1. Love Waves: Cause horizontal motion. They usually travel slightly faster than Rayleigh waves

2. Rayleigh Waves: Cause rolling motion like ocean waves.

5. Fault Plane

The flat surface along which there is slip during an earthquake.

6. Aftershocks

Earthquake -is the sudden shaking of the Earth's surface caused by the release of energy stored in rocks.

-this energy is released in the form of seismic waves.

Causes:

Movement of tectonic plates.

Rising magma during volcanic activity.

Faults- is a fracture or break in the Earth's crust where movement occurs.

Blocks of Faulted Rock:

Hanging Wall: The block of rock above the fault plane.

Foot Wall: The block of rock below the fault plane.

Types of Faults

Normal fault

Reverse fault

Strike-slip fault

1. Normal Faults:

Describe when the hanging wall move downward relative to the footwall.

Rocks move apart due to tension.

2. Reverse Faults:

Describe when the hanging wall move upward relative to the footwall

Rocks are pushed together due to compression,

3. Strike-Slip Faults: Rocks slide past each other horizontally due to shearing

forces.

Parts of an Earthquake

1. Focus (Нуросenter)

The point inside the Earth where the earthquake originates.

It is the location where stress is first released, causing seismic waves to radiate outward.

2. Epicenter

The point on the Earth's surface directly above the focus

This is the location reported by seismologists and is often the area that experiences the most damage

Areas where we felt the shaking.

3. Fault

Smaller earthquakes that occur after the main shock, as the crust adjusts to the displacement.

Earthquake Intensity and Magnitude

Magnitude: Measures the energy released at the source

Richter scale- used to measure the magnitude of an earthquake.

Intensity: Measures the effects or damage caused

Mercalli scale - used to measure the intensity of earthquake.

Continental Plate Boundaries

Continental plate boundaries are the regions where tectonic plates meet, interact, and cause geological activities like earthquakes, mountain formation, and volcanic activity. These boundaries can be classified into three main types based on the direction of plate movement:

1. Convergent Boundaries

Description: Plates move toward each other, causing compression.

Features and Examples:

Formation of mountain ranges (e.g., the Himalayas, formed by the collision of the Indian Plate and the Eurasian Plate).

Subduction zones can form when an oceanic plate converges with a continental plate, leading to volcanic activity (e.g., the Andes Mountains).

Impact: High seismic activity, mountain building, and volcanic eruptions.

2. Divergent Boundaries

Description: Plates move apart, creating tensional forces.

Features and Examples:

Formation of rift valleys (e.g., the East African Rift).

New crust is created as magma rises to fill the gap (e.g., the Red Sea, where the African and Arabian plates are diverging).

Impact: Formation of new landmasses, earthquakes, and volcanic activity.

3. Transform Boundaries.

Description: Plates slide past each other horizontally.

Features and Examples:

Creation of fault lines (e.g., the San Andreas Fault in California).

No significant crust is created or destroyed.

Impact: Frequent shallow earthquakes along the fault lines.

The rotation of the Earth (Coriolis Effect) causes the air to rotate:

• Counterclockwise in the Northern Hemisphere.

• Clockwise in the Southern Hemisphere.

This rotation organizes the storm into a cyclonic structure.

6. Weak Vertical Wind Shear

Wind shear refers to changes in wind speed or direction at different altitudes.

For typhoon formation, light wind shear is necessary to allow the storm to grow vertically without being disrupted.

Tropical Cyclones

Typhoon: Term used in the western Pacific.

Hurricane: Term used in the northeastern Pacific and Atlantic.

Cyclone: Term used in the Indian and South Pacific Oceans.

Key Difference: The terms differ based on the geographical region.

Philippine Area of Responsibility (PAR)

Defined region in the Northwestern Pacific monitored by PAGASA.

PAGASA tracks and names typhoons that enter or develop in the PAR.

Typhoon Statistics in the Philippines

Approximately 20 tropical cyclones enter the PAR annually.

The Philippines is highly prone to typhoons due to its location in the Pacific.

D

S

T

Tropical Depression (TD)

61 km/h OR LESS

Tropical Storm (TS)

62-88 km/h

Severe Tropical Storm (STS)

89-117 km/h

Typhoon (TY)

118-184 km/h

Super Typhoon (STY)

185 km/h or higher

WIND SIGNAL 1

WIND SIGNAL 2

WIND SIGNAL 3

WIND SIGNAL 4

WIND SIGNAL 5

Modified Public Storm Warning System

Signal No. 1 (Lead time 36 hours)- 30-60 kph mximum sustained winds; expected impact of the wind: no damage to very light damage

Signal No. 2 (Lead time 24 hours) -61-120 kph maximum sustained winds; light to moderate damage expected.

Signal No. 3 (Lead time 18 hours) 121-170 kph maximum sustained winds; moderate to heavy damage expected.

Signal No. 4 (Lead time 12 hours)- 171-220 kph maximum sustained winds; heavy to very heavy damage expected.

Signal No. 5 (Lead time 12 hours) more than 220 kph maximum sustained winds; very heavy to widespread damage expected.

COMETS, METEORS AND ASTEROIDS

Comets

-is a Celestial objects made of ice, dust, and rocky material. Known as dirty snowball or cosmic snowball.

-when near the Sun, ice vaporizes to form a coma (fuzzy outer layer) and tail.

Parts of a Comet:

1. Nucleus: Solid core.

2. Coma: Cloud of gas and dust surrounding the nucleus.

3. Tail: Formed when a comet approaches the sun. It is also formed by solar wind pushing dust and gas away from the Sun.

Origin:

1. Kuiper Belt: Doughnut-shaped region found beyond Neptune. It is where we found all the short period comets.

Short Period Comets- those which take less than 200 years to complete an orbit around the sun.

Example

Halley's Comet: is a Short-period comet visible every 75-79 years.

2. Oort Cloud: Spherical region found far beyond Pluto. The place where we see all the longer period comets.

Longer Period Comets- those which take more than 200 years to complete an orbit around the sun.

Famous Example:

Halley's Comet: is a Short-period comet visible every 75-79 years.

Asteroids- it is a rocky fragment orbiting the Sun, also called minor planets.

Origin: Orbits are more rounded than comets

Found mainly in the Asteroid Belt between Mars and Jupiter.

Types of Asteroids:

1. C-Type: Carbon-rich.

2. S-Type: Silicate-rich.

3. M-Type: Metal-rich.

Key Facts:

Ceres: The largest asteroid, discovered in 1801.

Meteoroids, Meteors, and Meteorites

Meteoroid: A small, rocky or metallic body found in the outer space.

Meteor: The streak of light produced when a meteoroid burns up in Earth's atmosphere.

Meteorite: The remains of a meteoroid that reaches and landed on the Earth's surface.

Meteor Shower- it is a natural event or phenomenon caused by Earth passing through debris left by comets or asteroids.