Earth Science

24

9b. Students know the principal natural hazards in

different California

regions and the geolog

ic basis of those

hazards.

California is subject to a va

riety of natural hazards. Active fault zones generate

earthquakes, such as those of the San Andreas fault system. Uplifted areas with weak underlying rocks and sediments are prone to landslides, and the California Cascade mountains contain both active and dormant volc

anoes. The erosion of

coastal cliffs is

expected, caused in part by the energy of waves eroding them at their bases. When earthquakes occur along the Pacific Rim, seismic sea waves, or tsunamis, may be generated.

ACTIVE FAULT ZONES LANDSLIDES EROSION TSUNAMIS ACTIVE VS. DORMANT VOLCANOES

Earthquake activity in Califor

nia is primarily caused by-

From:

Test Bank 07-08

A

the lowering of aquifer levels

B

the interaction of tides with the coast

C

mining activity during th

e nineteenth century

D

plates grinding past each

other along active faults

SOURCE: Test Bank 08-09 Diff LEVEL: II

9c. Students know the importance of water to society, the origins of California’s fresh water, and the relationship between supply and need.

Water is especially important in California

because its economy is based on agriculture

and industry, both of which require large quan

tities of water. Calif

ornia is blessed with

an abundance of fresh water, which is supp

lied by precipitation an

d collected from the

melting of the snowpack in watersheds lo

cated in the Sierra Nevada and in other

mountain ranges. This process ensures a sl

ow runoff of water following the winter

rains and snowfall. But the water is not dist

ributed evenly. Northern California receives

most of the rain and snowfall, and southern

California is arid to semiarid. The natural

distribution of water is adjusted through en

gineered projects that transport water in

canals from the northern to the

southern part of the state.

WATER RESOURCES DAMS WATERSHEDS SNOW PACKS SLOW RUN-OFF PRECIPITATION WATER PROJECTS ARID, SEMI-ARID

Why is it necessary to include

data on snowpack when studying

hydrologic [water supply]

conditions in California?

A

95% or more of yearly precipitati

on in California is falling snow.

B

Melting snow contributes significa

ntly to California’s water supply.

C

Water “locked” as snow is not

available for use by California.

residents. D

Most dams in California have fr

ozen because of abnormal low

temperatures. SOURCE: Test Bank 09-10 Diff LEVEL: II