EQ Lab (2)

.pptx

School

Georgia State University *

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Course

1121

Subject

Geology

Date

Oct 30, 2023

Type

pptx

Pages

Uploaded by ConstableHawk4507

Earthquakes Lab Earthquake seismology methods Name: GEOL 1121K Earthquakes are a fact of life on Earth and mark distinct moments in history especially when there are devasting effects on communities around the world. Not only do they result in casualties, but they can cause damage to vital infrastructure, housing, and other basic services. The earthquakes that make the news are usually the big ones. For example, the magnitude of the 2004 Indian Ocean earthquake that resulted in a quarter million casualties was a 9.2 magnitude. The 1906 San Francisco earthquake was a magnitude 7.9. The catastrophic 2010 Haiti earthquake was a magnitude 7.0.. Oklahoma experienced human-induced earthquakes as large as magnitude 5.8; this caused building damage and much public dismay. But below magnitude 3, few people are likely to feel an earthquake, even in populated areas. One would think, given our knowledge of earthquakes, that humans would avoid these locations – however, the very faults of the Earth also create its greatest advantages. It is extremely common to find human settlement along fault lines where earthquakes occur most frequently. Recent studies have revealed that there may be more to the pattern than previously thought. Tectonically active plates may have produced greater biodiversity, more food, and water for our human predecessors. Certain landscape features formed by tectonic processes such as cliffs, river gorges, and sedimentary valleys create environments that support access to drinking water, shelter, and an abundant food supply. Lab Outline • Part 1: Time-Travel Curves • Part 2: Nomograph, Seismographs, and Time-Distance chart • Part 3: Earthquake Triangulation • Lab Guide Deliverables • Powerpoint document • Triangulation map It is not known when exactly earthquakes will occur, but as scientists, we can estimate where they will happen, and roughly how big they will be. This laboratory exercise introduces you to some of the basic procedures used to estimate earthquake time and source locations. After the completion of this lab, you will have learned how to read seismograms to estimate P- and S-wave arrival times, determine magnitude energy, use a travel-time curve to obtain distances from the seismometers to the epicenter, and be able to map epicenters using Google Maps. Volcanoes and earthquakes are not randomly distributed around the globe. Instead they tend to occur along limited zones or belts. With the understanding of plate tectonics, scientists recognized that these belts occur along plate boundaries.

Some food for thought…

1. How long would it take a P-wave to travel 8,000 km? Approximately 11 minutes and 20 seconds. PART 1 : Be sure to read the Lab Guide packet first before starting the lab. It contains useful literature and examples to help you complete the lab. Answer the following questions by using the time travel curve charts below. Show your work by using the lines provided to mark the graph. Move and resize the lines (horizontally and vertically) as needed.

2. How far can an S-wave travel in 9 minutes? 22 minutes and 20 seconds

3. If an earthquake occurs at 02:11:20, at what time do you expect the S-wave to arrive at a seismic station that is 9,000 km away? Show your work by typing out your calculations. Distance from station= 9000 km 2:11:20 + 0:22:20 = 2:33:40 Time of occurrence = 2:11:20 pm it will arrive at 2:33:40 wave = 00:22:20

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