Grade 10 SCIENCE | Quarter 1 Module 2 | Triangulation Method DEMO

Summary

In this video, the instructor demonstrates how to locate the epicenter of an earthquake using the triangulation method. By utilizing data from three seismic stations (located in Iloilo, Naga, and Tarlac), students learn how to calculate the distance of the epicenter from each station based on the arrival times of seismic waves. The video explains the conversion of distances to scale and guides viewers through drawing circles on a map to identify the point of intersection, which marks the earthquake's epicenter. The process emphasizes hands-on application of seismic wave principles and triangulation for earthquake detection.

Takeaways

• 😀 The triangulation method is used to locate the epicenter of an earthquake by drawing circles based on seismic wave data from three different seismic stations.
• 😀 Triangulation involves using three seismic stations to find the intersection of circles, which represents the epicenter of the earthquake.
• 😀 There are two main types of seismic waves: body waves (which include primary and secondary waves) and surface waves (which include love and rayleigh waves).
• 😀 Primary waves (P-waves) are faster than secondary waves (S-waves), which allows seismic stations to record the arrival times of P-waves first.
• 😀 The time difference between the arrival of P-waves and S-waves at seismic stations is used to determine the distance from the epicenter to the station.
• 😀 To perform triangulation, the distance from each seismic station to the epicenter is converted to a scale that fits the map (e.g., 1 cm = 100 km).
• 😀 A drawing compass (or an improvised version using a pencil and string) is needed to draw the circles representing the seismic wave radii.
• 😀 The calculated distances from each station (in kilometers) are used to determine the radius of each circle on the map.
• 😀 The point where all three circles intersect indicates the location of the earthquake's epicenter.
• 😀 In this demonstration, Iloilo, Naga, and Tarlac are used as the seismic stations, and the calculated radii result in the epicenter being located in Batangas.

Q & A

What method is used to locate the epicenter of an earthquake in this video?

The triangulation method is used to locate the epicenter of an earthquake. It involves using three different seismic stations to create circles on a map, and the point where all three circles intersect indicates the epicenter.

Why is the method called 'triangulation'?

It is called triangulation because it involves three points (seismic stations), much like the three sides of a triangle, to determine the location of the epicenter.

What are the two main types of seismic waves mentioned in the script?

The two main types of seismic waves mentioned are body waves and surface waves. Body waves are further divided into primary waves (P-waves) and secondary waves (S-waves), while surface waves are divided into love waves and Rayleigh waves.

How do primary waves (P-waves) help in locating the epicenter?

Primary waves (P-waves) travel faster than secondary waves (S-waves). The time difference between the arrival of P-waves and S-waves at a seismic station helps in calculating the distance to the epicenter, which is essential for triangulation.

What is the role of the time difference between P-waves and S-waves?

The time difference between the arrival of P-waves and S-waves helps determine the distance between the seismic station and the epicenter. The greater the time difference, the further the epicenter is from the station.

What materials are required for the triangulation demonstration?

The materials required are a drawing compass (or an improvised compass using a pencil and string), a ruler, and a pen or pencil for calculations. Additionally, the distance data for the seismic stations is needed.

How do you convert the epicenter distance to the correct scale for drawing the circles?

To convert the epicenter distance to the correct scale, divide the actual distance in kilometers by the scale factor (in this case, 100 kilometers). For example, 520 kilometers divided by 100 equals 5.2 centimeters, which is the radius of the circle for Iloilo.

What is the significance of the scale 1 cm = 100 km in this demonstration?

This scale is used to convert the actual distance of the epicenter from each seismic station (in kilometers) into a smaller, manageable length (in centimeters) to accurately draw the circles on the map.

What does it mean when the three circles intersect on the map?

When the three circles intersect, the point of intersection represents the location of the earthquake's epicenter.

How does the triangulation method help identify the epicenter?

The triangulation method helps identify the epicenter by using data from three seismic stations. By drawing circles around each station based on the calculated distance to the epicenter, the point where all three circles intersect reveals the location of the epicenter.