O
N FEBRUARY 27,
2010, AT 3:34 AM
LOCAL TIME, AN
earthquake measuring 8.8 occurred
approximately 11 kilometers
(7 miles) off the coast of Chile,
resulting in 486 fatalities and
widespread property damage.
This powerful quake prompted
seismologists to estimate that the
length of the day was shortened by
1.26 microseconds and Earth’ s axis
moved by 8 centimeters (3 inches).
In addition, the event laterally
displaced cities, including
Concepción by more than 3 meters
(10 feet) and Santiago approximately
24 centimeters (10 inches).
F O C U S O N C O N C E P T S
To assist you in learning
the important concepts in this
chapter, focus on the following
questions:
What is an earthquake?
What are the types of
earthquake waves?
How is the epicenter of an
earthquake determined?
Where are the principal
earthquake zones on Earth?
How is earthquake strength
expressed?
What are the main factors that
affect the amount of destruction
caused by seismic shaking?
What is a tsunami?
How did Earth acquire its layered
structure?
What are the major zones of
Earth’s interior?
How do continental crust and
oceanic crust differ?
The Borde Rio apartment building in Concepción,
Chile, was toppled by an 8.8-magnitude earthquake
on February 27, 2010 (Photo by Pilar Olivares/Reuters)