Mercalli Scale

​Lab #2:

Measuring Earthquakes

This lab is worth 90 minutes and must be completed by the end of the marking period.

We will only work on it in class for 1 and a half days

​Part 1: Mercalli Scale

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Today, we will learn of one method used to measure earthquakes. An earthquake’s intensity is a measurement of ground shaking based on damage to structures and changes felt and observed by humans. It is expressed in Roman numerals on the Mercalli Scale

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​Objective: By the end of this lab I will be able to locate the epicenter of an earthquake based on observational data

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Here we have the Modified Mercalli Scale. It measures the shaking you feel during an earthquake. As you can see here, as the numbers get higher, the more you feel the shaking

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We will be using data from reports of an earthquake that struck California in 1989 and the Modified Mercalli Scale of Intensity to see where it might have originated from. ​

​Procedure - Part 1

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1. On the following slides, you will see reports that were called into a radio station after the quake​

2. For each slide, use the Modified Mercalli Scale ​on slide three to estimate the Mercalli rating at that Location

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Draw

Using the information you have gathered and place an X on where you think the earthquake epicenter is

​Part 2: The Richter Scale

​Some text here about the topic of discussion.

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We will now explore the second and more reliable method used to measure earthquakes. This method requires you to know your distance from the quake and the amplitude of the waves

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​Objective: By the end of this lab I will be able find the richter scale measurment, wave amplitude, and distance to epicenter

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​Amplitude is how high or low the wave goes on the paper, as shown below

​Procedure - Part 2

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1. ​Answer the questions below for each earthquake.

2. First draw the line on the scale, the answer the question on the slide that follows​

Draw

1.    Use the set of instructions on the previous page and the seismogram and scales below to determine the Richter magnitude of an earthquake that was located 500 kilometers from the seismic station. The height of the largest S-wave was 20mm

Draw

A seismic station located 60 km from the epicenter of an earthquake recorded the maximum height of the S-waves to be 50 mm

Draw

An earthquake with a Richter magnitude of 1.5 caused an S-wave of 1 mm to be recorded on a seismogram

Draw

A seismic station located 40 km was determined to have a Richter magnitude of 3.5. What was the height of the largest S-wave?

​Part 3: Regents Connections

​Some text here about the topic of discussion.

Multiple Choice

The magnitude of an earthquake is a number that represents the

• arrival time of the first P-wave

• difference in arrival times between P- and S- waves

• distance to the epicenter

• energy released by an earthquake

Multiple Choice

Which location would most probably have issued the report: “Many structures shifted off foundations”?

• New Madrid

• Syracuse

• Pittsburgh

• Nashville