Organize

Learn

Connect

Instructors now have an easy way to collect students’ online quizzes with the Norton Gradebook without flooding their inboxes with e-mails.

Students can track their online quiz scores by setting up their own Student Gradebook.

Chapter 10: A Violent Pulse: Earthqukes

Geotours

Download Geotours.

Getting Started :

If you haven’t done it already, download Google Earth™ and install it on your computer.
If you haven’t done it already, download the Geotours.kmz file and save a copy to your desktop. (The Geotours.kmz file contains the Geotours for all chapters, so you only need to download this once!)
By downloading Geotours.kmz you acknowledge that it was created solely to accompany Steve Marshak's Earth: Portrait of a Planet and Essentials of Geology and is limited to use with only Steve Marshak's Earth: Portrait of a Planet and Essentials of Geology and may not be reproduced, stored in a retrieval system, or transmitted in any form by any means for any other purpose without the written permission of the publisher.
Double-click the Geotours.kmz file and Google Earth™ will open automatically.
In the left-hand sidebar you will see a Places menu, and in the Temporary Places folder you will see an EARTH_3e.kmz file. Double-click the file and you will see a list of Geotours for each chapter.
Then open the Geotour folder you want to explore! If you’d like to read more about the features of Geotours see Using Geotours, or go to our Helpful Resources section.

STOPS ON GEOTOUR 10: Seismically Active Faults

San Andreas Fault near Palmdale, California

See also Worksheet Problem 1
"What a Geologist Sees" Geofeatures: Garlock Fault, San Andreas Fault, Hughes Lake Sag Pond, Elizabeth Lake Sag Pond, Lake Palmdale Sag Pond, Offset Stream; Mountains: San Gabriel Mountains, Tehachapi Mountains; Faults Garlock Fault Trace (approx.), San Andreas Fault Trace (approx.); Water: Offset Stream
San Andreas Tour

San Andreas Fault, San Francisco

See also Worksheet Problems 2-3

Salt Lake City, Utah

See also Worksheet Problem 4

Tsunami Damage, Banda Aceh

See also Worksheet Problem 5
"What a Geologist Sees" Geofeatures: Epicenter; Overlay: Regional Plate Tectonics

GEOTOUR 10 WORKSHEET

In many locations, faulting during an earthquake ruptures the ground. Below, we visit examples of fault zones that have left a mark on the land surface. The journey also illustrates potential hazards associated with seismic activity.

San Andreas Fault near Palmdale, California
1. A number of distinct geologic features develop along continental strike-slip faults, as illustrated by figures within Chapter 10 of the text. Excellent examples are exposed in southern California, where the San Andreas Fault delineates the boundary between the Mojave Desert and the San Gabriel Mountains.

(a) Double click on the placemark for Problem 1a. You are looking at a small, elongate body of water. What is this feature?

(b) Double-click on the placemark for Problem 1b. You are looking at a small, elongate hill. What is this feature?

(c) Orient your image so that you are looking straight down, and zoom out to100 km so that you can see the placemarks for both Problem 1a and Problem 1b. What is the compass orientation of the fault between these two locations?

(d) Double-click on the placemark labeled “Offset Stream” in the WAGS folder for the San Andreas Fault near Palmdale, California, folder. Based on the observed offset, is the sense of slip on the fault “right-lateral” or “left-lateral?”

Measure the amount of offset. Assume that the rate of slip on the fault is about 6 cm/year. How many years has it taken to develop the observed offset of the stream?

San Andreas Fault, San Francisco
2. The placemarks for Problems 2a and b highlight features of the San Andreas Fault near the city of San Francisco, about 550 km NW of Palmdale.

(a) Double click on the placemark for Problem 2a. You are looking NW along the fault trace, just SW of highway 280. What landscape feature delineates the fault trace?

Why did this feature form?

(b) Double-click on the placemark for Problem 2b. You will go to a point on the coast near Fort Ross (notice the linear, fault-controlled valley just east of the placemark). The placemark for Problem 2b highlights one of a series of scallop-shaped cliffs along the shore. Identify the feature and explain how it formed.

3. The placemark for Problem 3 lies at the north end of the San Andreas Fault, where it intersects two other plate boundaries. Turn on the “Geographic Features” layer in the Layers panel, and you will see that a chain of volcanoes (the Cascade Volcanic Arc) lies near the coast north of the end of the San Andreas Fault. Use your book to help answer the following:

What is the point of intersection between three plate boundaries called?

What are the types of plate boundaries that intersect here?

What are the three plates that surround this point?

Salt Lake City, Utah
4. The placemark labeled Problem 4 highlights one of a series of triangular-shaped cliffs, or “triangular facets,” formed along the front of the Wasatch Mountains in the Provo area south of Salt Lake City.

(a) Are these features flat irons or fault-truncated ridges? (Hint: Fly in closer and rotate the view to help you visualize the features.)

(b) Salt Lake City and Provo lie on the hanging-wall block of the fault that delineates the boundary between a broad basin (to the west) and the Wasatch Mountains (to the east). Assuming the west face of the Wasatch Mountains, at lower elevations, is the fault scarp, is this fault a normal fault or a reverse fault?

Tsunami Damage, Banda Aceh
5. Double-click on Image G10.10–12 and you will be looking down on the Banda Aceh area, where the 2004 tsunami inflicted catastrophic damage.

(a) Zoom down to an elevation of about 10 km and examine the region north of the Image G10.10–12 placemark along the shoreline on the north side of the city. What is the width of the devastated area (in km) as measured along the shoreline?

(b) In the “WAGS” folder for this area, double-click on the overlay “Regional Plate Tectonics”—you will zoom out to an altitude of about 3,600 km. Then, make the map semi-transparent. Note the position of the “Epicenter” placemark. Which tectonic plate was subducted beneath which overriding tectonic plate at this locality?

See also USGS Real-Time Earthquake and Plate Boundary Mapping in Google Earth™, to access information from around the globe updated every 5 minutes.

Simply click on one of the KML feeds and open it in Google Earth™. The maps will display earthquakes and plate boundaries, showing the latitude and longitude of the epicenter by a dot. The dot color indicates the depth of the hypocenter, while its size represents the magnitude of the event. Watch as the earthquakes of the last week pop up as dots on the map. Even though the map shows only a week's worth of data, you can easily spot the seismic belts that delineate plate boundaries, as well as the particularly active intracratonic seismic zones. Note that at lower elevations, your map will show a grid on the Earth's surface; the grid will disappear if you zoom out to a distance of over 9,500 km.

First Name:
Last Name:
Your Email Address:
Your Professor's Email Address:

Print this Page « Return to Chapter 10 Study Plan

StudySpace: Chemistry 2e.