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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Fill in the Blanks

Caller 1: “Hi, this is Charles from the hospital. We only had slight to moderate damage in the new, wellbuilt Children’s Care building. The building containing most of our records was old and poorly built; damage there was considerable.”

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Caller 2: “Hello my name is Roy, and I’m calling from the RQB Ranch. We were just sitting around the kitchen table, when suddenly coffee sloshed out of all our cups. Several cabinet doors opened up and dishes fell and broke.”

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Caller 3: “Hi Jake, I’m Susan calling from the Faithful Church. When the earthquake struck, our bell tower collapsed.”

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Caller 4: “Hi. This is Jo from Southside City Junior High School. Students felt it and did the drop, cover, and hold on drill. We only had slight damage to the building, just some cracked plaster in the walls. A few pictures also fell.

Fill in the Blanks

Caller 5: “Hey Jake, this is Hank and I’m calling from the basement of the First Bank in the center of Wattsville. This old building has partially collapsed and people are trapped down here. Please send help!

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Caller 6: “Hi, this is Fernando. I work at the Sunrise Senior Center. Many of our clients were frightened. All our supplies fell off the shelves.”

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Caller 7: “Hello Jake, this is Debbie. We were picnicking at the Great Bend Park. When the quake struck, it woke up Granny and we saw trees and a flagpole sway back and forth.”

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Caller 8: “Jake, this is Gene at White Water Manufacturing. All the heavy furniture in the showroom was moved by the quake, and some of the plaster cracked and fell off the walls.”

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Caller 9: “Hi, this is Diana calling from Happy Slurps Ice Cream. Over here we thought that a big truck had hit the building.”

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Caller 10: “Hi Jake, this is Ken at River City Video. Our large collection of DVDs fell off the shelves and onto the floor, and all our posters fell off the walls.”

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Caller 11: “Hi Jake, this is David from Wattsville University. Everyone in our class felt the quake. Good buildings were slightly damaged, and some of the older, more poorly built buildings had more damage.”

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Caller 12: “Hello Jake, This is Steve from the South End Mall. All the shoppers were having a hard time standing during the quake. We had a lot of breakage, especially in our furniture shops.”

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Caller 13: “Hello Jake, this is Martha at Cottage Inn. All of our customers were frightened. Nearly all of our little cottages moved off their foundations.”

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Caller 14: “Hi Jake, this is Marty at Big Bear Ski Resort. The quake rattled our dishes and windows. I saw some parked cars rocking. Most folks who were outdoors didn’t feel the shaking.”

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

Fill in the Blanks

Earthquake Magnitude:

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

Fill in the Blanks

Earthquake Magnitude:

Draw

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

Fill in the Blanks

Distance to Epicenter:

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?

Fill in the Blanks

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