Earth Science: Seismic Waves and Geology

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Questions and Answers

What is the primary distinction between P-waves and S-waves?

P-waves travel faster than S-waves. (correct)

P-waves can only travel through solids, while S-waves can travel through both solids and liquids.

S-waves are the first to arrive at a seismic station.

P-waves do not generate seismic noise.

Why is it necessary to use three different seismic stations to locate the epicenter of an earthquake?

To form a triangulation based on the difference in arrival times. (correct)

To detect both P-waves and S-waves simultaneously.

To ensure that the equipment is functioning properly.

To average the readings for more accurate results.

What type of wave only travels on the surface of the Earth?

Body wave

Primary wave

Surface wave (correct)

Secondary wave

What mechanism generates the seismic waves associated with earthquakes?

Tectonic plate movement. Signup and view all the answers

What does the term focus refer to in the context of earthquakes?

The point within the Earth where energy is released. Signup and view all the answers

Which of the following is a characteristic of S-waves?

They are the second to arrive at a seismic station. Signup and view all the answers

What instrument is used to record the motion of the ground during an earthquake?

Seismograph Signup and view all the answers

What role does the difference in arrival time of P-wave and S-wave play in seismic analysis?

It is used to calculate the distance to the epicenter. Signup and view all the answers

Which type of seismic wave is recorded first in a seismic station?

P-wave Signup and view all the answers

Where is the location of active volcanoes, earthquake epicenters, and major mountain belts?

Along the edges of the plates Signup and view all the answers

How is the distribution of earthquake epicenters, active volcanoes, and major mountain belts characterized?

The distribution of earthquake epicenters is different from active volcanoes and major mountain belts Signup and view all the answers

What is the definition of a seismic wave?

Energy released during an earthquake Signup and view all the answers

What is a plate boundary?

A gap or crack between two tectonic plates Signup and view all the answers

What type of seismic wave travels through the Earth's interior?

P-wave Signup and view all the answers

Which of the following correctly identifies the lithosphere?

The rigid outer layer of the Earth Signup and view all the answers

What characterizes the S-wave in seismic activity?

It cannot travel through liquids Signup and view all the answers

What does the radius of each circle represent when locating the epicenter of an earthquake?

The distance from the earthquake to the seismic recording station Signup and view all the answers

In the improvised geometry compass method described, what material is primarily used to create the compass?

String and pencil Signup and view all the answers

What should you do after drawing all three circles to find the epicenter?

Locate the point of intersection of the three circles Signup and view all the answers

How is the distance on the map represented in relation to the actual distance?

1 cm = 400 km Signup and view all the answers

What is the first step in using the improvised geometry compass?

Tie a piece of string low down around a pencil Signup and view all the answers

What should be maintained while drawing the circle with the improvised compass?

The string should be tight and pencil upright Signup and view all the answers

When drawing circles with the impromptu compass, where should the string be held?

At the length of the radius away from the pencil Signup and view all the answers

Which of the following steps is NOT part of using the improvised geometry compass?

Cut the string based on the radius needed Signup and view all the answers

What is the first step to locate the earthquake epicenter using the triangulation method?

Get distance data from at least three different seismic stations. Signup and view all the answers

How do seismologists determine the distance to the earthquake epicenter?

By multiplying the difference in arrival time of waves by 8 km. Signup and view all the answers

What is the required number of seismic stations to accurately locate the epicenter of an earthquake?

Three or more stations are required. Signup and view all the answers

Which of the following methods is used to represent the distances from the seismic stations on a map?

Drawing circles around each station. Signup and view all the answers

What is the scale ratio used to convert the distance from kilometers to centimeters in this procedure?

1 cm = 400 km Signup and view all the answers

If the distance recorded by a seismograph is 1640 km, what is the corresponding scaled distance in centimeters?

4.1 cm Signup and view all the answers

What is the purpose of intersections in the triangulation method?

To identify the location of the epicenter. Signup and view all the answers

What equipment is necessary for the triangulation method according to the procedure?

A ruler, pencil, and a compass. Signup and view all the answers

How are active volcanoes related to plate tectonics?

They are found mostly at tectonic plate boundaries. Signup and view all the answers

What causes earthquake epicenters to be located along plate boundaries?

Tectonic plates friction can lead to the release of energy. Signup and view all the answers

Which of the following is a major mountain belt that is influenced by tectonic activity?

Himalayas Signup and view all the answers

Which statement about the distribution of earthquakes is accurate?

They are concentrated along tectonic plate boundaries. Signup and view all the answers

What is a consequence of plate tectonic movement on landforms?

Creation of rift valleys and mountain ranges. Signup and view all the answers

Why might the location of volcanoes serve as indicators of tectonic activity?

Volcanoes often form where tectonic plates converge. Signup and view all the answers

Which of the following correctly describes an earthquake?

A sudden release of energy in the Earth's crust. Signup and view all the answers

The primary factor contributing to the formation of mountains is:

Tectonic plate collisions and movements. Signup and view all the answers

Study Notes

Seismic Waves

Seismic waves generated by tectonic plate movement release energy throughout the Earth.
Two primary types of seismic waves: body waves and surface waves.
P-wave (primary wave) is the first to be recorded at seismic stations, traveling the fastest, followed by the S-wave (secondary wave).
Surface waves arrive last, traveling only along the Earth's surface.

Earthquake Fundamentals

The focus is the point within the Earth where energy is released during an earthquake.
The epicenter is directly above the focus on the Earth's surface.
Seismographs are used globally to record seismic activity and measure ground motion.

Epicenter Location

Triangulation method is used to determine the precise location of an earthquake's epicenter.
Requires distance data from at least three different seismic stations.
Distances to the epicenter can be calculated by multiplying the time difference of P-wave and S-wave arrivals by 8 km/s.

Global Distribution Patterns

Active volcanoes, earthquake epicenters, and major mountain belts are primarily located along the edges of tectonic plates.
Their distribution correlates with the boundaries of tectonic plates, differing from locations in the middle of plates or continents.

Geologic Terms

Lithosphere: Rigid outer part of the Earth, comprising the crust and upper mantle.
Plate Boundary: Crack or gap between two tectonic plates.
Seismic Wave: Energy waves produced by earthquakes.
Continental Crust: Thicker and less dense type of crust found under continents.
Oceanic Crust: Denser, thinner type of crust found beneath ocean floors.

Earthquake Measurement

Seismographers record different seismic waves to analyze and locate earthquake epicenters.
The difference in arrival times helps estimate distances from the seismic station.
Example distances from seismic stations for triangulation: South Caloocan at 1640 km, Marikina at 1600 km, Muntinlupa at 1040 km.

Learning Activities

The Seismic Race provides insight into the characteristics of seismic waves, emphasizing the speed difference between P-wave and S-wave.
Journey to the Center of the Earthquake reinforces understanding of triangulation for locating epicenters through practical measurements and mapping skills.
Critical thinking questions encourage students to reflect on their understanding of seismic activity and plate tectonics.

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Description

Test your knowledge on seismic waves and their characteristics, along with the geographical distribution of earthquake epicenters, active volcanoes, and major mountain belts. This quiz covers key concepts in earth science regarding tectonic activities. Challenge yourself and discover how well you understand these fundamental processes.