Laboratory Manual for Introductory Geology 4e

GEOTOURS EXERCISE 17
Understanding Tsunami Devastation
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Exploring Geology Using Google Earth
1. Visit digital.wwnorton.com/geolabmanual4
2. Go to the Geotours tile to download Google Earth Pro and the accompanying Geotours
exercises file.
On December 26, 2004, the third largest
earthquake in recorded history occurred in
the subduction zone off the western coast of
Sumatra, Indonesia. This earthquake produced
a tsunami that devastated coastlines all around
the Indian Ocean. Expand the Geotour17
folder in Google Earth by clicking the triangle
to the left of the folder icon to begin exploring
the effects of this disastrous wave.
(a) Check the Tsunami Travel Times overlay
and then check and double-click the Horn
of Africa placemark. Check the Tsunami
Travel Times link to see how the contours
correspond to travel time, then close the
balloon. How long (hrs) did it take the
tsunami from the 2004 earthquake to
travel from Sumatra to the Horn of Africa?
(b) Check and double-click the Epicenter placemark (leave the Tsunami Travel Times overlay and Horn of Africa
placemark checked). Use the Path tab on the Ruler tool to measure the distance (km, roughly perpendicular to
contours) from the earthquake epicenter to the Horn of Africa. Use this distance and the answer to question (a) to
calculate an average velocity (km/hr) for the tsunami.
(c) Check and double-click each of the Lho-nga and Leupung placemarks in turn to fly to before/after imagery of two
coastal areas in Sumatra that were devastated by the 2004 Indian Ocean Tsunami (turn off the Tsunami Travel
Times overlay). What happened to sand from the beaches?
(d) In general, were buildings near the coast a safe haven to ride out the tsunami? Why or why not?
(e) Check and double-click the Peninsula placemark to fly to a peninsula halfway between the two cities. Were all areas
near the coast devastated? What lessons about safety in tsunami-prone areas can be learned from this location
(toggle the clock icon for historical imagery off to see present-day imagery . . . where did new construction occur)?
17.5 WHEN SHORELINES BECOME DANGEROUS
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