Environmental Geology 103L Fall 2015
Team ___________________________ names ___________________________ ___________________________ ___________________________
Lab 2: Earthquakes and Earthquake Hazards I. WHERE DID THAT COME FROM? LOCATING AN EARTHQUAKE. Complete Exercise 16.4 Steps 2 & 3 in the lab manual on page 415. You should do Step 1 for practice before you move on to Step 2.
Seismic arrival times
Arrival times and delays between seismic waves Seattle Boston
Los Angeles
P-Wave S-Wave Love Wave Raleigh Wave Delays between seismic waves S-P Love-S Raleigh-Love Choose from the following distances: 3000km, 2000km, 2500km Distance to epicenter from Seattle:_____________km Boston____________km
Los Angeles___________km
Complete step 4 using the website below to triangulate the location of the epicenter. http://www.freemaptools.com/radius-around-point.htm
Scroll down past the map to the Radius box. Enter your radius in kilometers. (The radius should be the distance away from the city that the earthquake occurred) Input latitude and longitude of the city. o Seattle lat: 47.5998° N long: 122.3346° W o Boston lat: 42.3645° N long: 71.0580° W o Los Angeles lat: 34.0547°N long:118.2415° W Click on Draw Radius. Repeat for the other 2 cities.
1. Describe the location of the epicenter of this earthquake:
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II. HOW DOES THE TYPE OF EARTH MATERIALS AFFECT EARTHQUAKE DAMAGE? In this section of the lab exercises, you and your teammates will explore how various types of earth foundation materials can dramatically affect the type of damages that can occur to buildings on the surface during an earthquake. You will first explore several interactive scenarios to learn how different types of building construction and ground materials behave under different magnitude earthquakes. Use the following weblink to access the Earthquake simulator:
http://www.cosmeo.com/braingames/makeaquake/index.cfm?title=Make%20a%20Quake Explore to determine detailed scenarios for building in earthquake prone areas. Try varying the Ground Type and Prevention Mechanism to determine which has the most impact on how destructive the earthquake is. Make sure to read the text after the simulation and don’t just describe the picture. The text has vital information about each scenario. Fill out the table below. Ground Type
Magnitude
Prevention Mechanism
Coastal
Superquake
Reinforced masonry
Coastal
Superquake
Result
Superquake
1. What style of building construction would be the safest for the scenario Coastal, Superquake?
2. For the Scenario Superquake and using the best building style from above, what type of earth foundation materials would be the safest during a superquake?
3. Out of all the types of earthquakes, building prevention mechanisms, types of foundations, which scenarios would generate the MOST DEVASTASTION?
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III. Earth materials underneath MUSC and the College of Charleston Below is a diagram showing the stratigraphy (the layers of rock and sediment) that are found beneath MUSC near the edges of the peninsula and the College of Charleston near the interior. Artificial Fill
Modern Beach Deposits
Ancient Beach Deposits
Ancient Beach Deposits
Wando Formation
Wando Formation
Examine the core models for each of these locations, along with the containers of materials that make up each individual layer (artificial fill, modern beach deposits, ancient beach deposits, and Wando formation). Write a short description of each layer in the chart below.
CORE LOCATION ARTIFICIAL FILL
A- MUSC
MODERN BEACH DEPOSITS
B -COFC NOT APPLICABLE NOT APPLICABLE
ANCIENT BEACH DEPOSITS WANDO FORMATION
1. Out of each layer, which do you predict would be the most stable during an earthquake? Artificial Fill
Modern Beach Deposit
Ancient Beach Deposits
Wando Formation
2. Why? Now take the container of artificial fill. Place several pennies vertically about halfway in the material, imitating the vertical walls of buildings or structures constructed on this ground material. Simulate an earthquake by gently tapping the container on the table. Observe what happens to the “buildings”. Repeat with each of the ground types.
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3. Which ground material was the most stable and why?
4. Which ground material was the least stable and why?
5. What happened to the buildings in this material during your simulated earthquake?
6. Which ground materials are most likely to experience liquefaction and why?
7. Which cores are more stable during earthquakes – MUSC or COFC and why?
8. If you had to build on the outer edge of the peninsula like MUSC is, how could you design a building to mitigate the effects of the unstable upper layers of ground materials? (Hint: think back to the simulation in Part III that allowed you to try out different types of buildings).
Part IV. EARTHQUAKE HAZARDS IN CHARLESTON If you are not native to Charleston, you may be wondering why we are looking at earthquake hazards of Charleston. Earthquakes don’t happen on the east coast, right? Charleston is, in fact, at risk for earthquakes. The last major earthquake to hit Charleston was in 1886. Watch the video “It Could Happen Tomorrow” and use the following websites to help you answer the questions below about the 1886 earthquake, and Charleston’s risk for future quakes. http://scearthquakes.cofc.edu/pdf/EQGuide2012.pdf http://earthquake.usgs.gov/regional/states/events/1886_09_01.php : This page includes a good summary of the events in 1886. Take a look at the historic photos also. 1. Is Charleston located on a current plate boundary? a. If not, please describe why there are earthquakes here.
2. What was the magnitude of the 1886 earthquake in Charleston?
3. What is the name of the fault zone along which this earthquake occurred?
4.
Look at the historic maps of the Charleston Peninsula posted on OAKS. How is the peninsula different today than it was in the 1700’s?
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Creating an Earthquake Hazard Map for Charleston Examine the geologic map of Charleston. This map shows what rock and/or sediment layers that you looked at in Part III can be found at the surface. The areas on the map that are made of artificial fill were once marshland that was filled in order to provide new land for building. Based on you results from Part III, determine which areas are at highest risk for damage when the next earthquake hits Charleston, and which areas are at lowest risk. Now, using the Charleston Topographic Map on the next page as your base map, create an Earthquake Hazards map of the Charleston peninsula, shading in areas of HIGH and LOW earthquake damage risk. Also highlight/indicate infrastructure that will be important in the aftermath of an earthquake, such a fire stations, hospitals, and evacuation routes (including bridges). Make sure to include a key on your map and a title.
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5. Which areas of the peninsula are most likely to experience liquefaction?
6. If an earthquake of the same magnitude as that which occurred in 1886, MM 7.3, happened today in Charleston, how would the devastation differ from what happened in 1886? Would it be worse or less? Why? Use the SCEEP website and consider the locations of the important infrastructure that you identified on your hazard map in your answer.
Earthquake damage in downtown Charleston 1. Walk to the Cistern and examine Randolf Hall. Built in 1829, this is one of the oldest buildings on campus. It was severely damaged in the 1886 earthquake. Identify at least 3 damage features visible on Randolph hall from 1886 earthquake? Use the handout on the following page to help you, and the photo of Randolph Hall taken after the earthquake below.
Extra Credit/Homework (your instructor will let you know which) Walk around downtown Charleston. Identify 3 other buildings/locations that show earthquake damage. Give location, type of damage. Bonus: Include photos. S on King st is a good way to go.
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