VOCABULARY
Fault:
a break or
fracture in Earth’s crust
along which movement
has taken place.
Landfill:
a site where soil has been
deposited by artificial means—often,
where garbage or rubbish has been
disposed of, then covered with dirt
and compacted.
Landslide:
an abrupt movement of
soil and bedrock downhill in
response to gravity. Landslides can
be triggered by an earthquake or
other natural causes.
Liquefaction:
the process in which
a solid (soil) takes on the
characteristics of a liquid as a result
of an increase in pore pressure and
a reduction in stress.
Sedimentary deposits:
accumula-
tion of solid particles that originated
from the weathering of rocks and
that have been transported or
deposited by wind, water, and ice.
Seismic:
of or having to do with
earthquakes.
Slump:
a type of landslide in which a
block of rock or soil moves along a
curved surface and rotates.
Tsunami:
a potentially destructive
ocean wave created by an
earthquake or other large-scale
disturbance of the ocean floor; a
seismic sea wave. This Japanese
word has the same form in both the
singular and the plural.
P ROC E DUR E
Teacher Preparation
(optional but highly recommended)
If at all possible, gather a selection of local geologic and soil maps in
advance. Make student copies of these maps or the appropriate portions
of them. If you are not familiar with maps of this type, invite a local
geologist or soil scientist to explain them.
A. Introduction
Have students read Master 2.5a, Background Reading: Site
Characteristics, as homework, or read it with them in class. Explain and
amplify any unfamiliar terms. Discuss the relationship between soils,
subsoil geology, and the suitability of a site for building. Explain that
the locations of roads, utility lines, reservoirs, and other facilities also
involve seismic considerations.
B. Lesson Development
1. Divide students into small groups. Give each group one copy of
Master 2.5c, Surface Map, Soil Map, Geologic Map, and Hazard Map
(4 pages). Use the map keys to review the special symbols and
markings on each map. Instruct students to interpret the information
shown on the specialized maps and transfer it to the surface map.
2. As a class, discuss what type of building would be most earthquake
resistant in each area of the maps the groups have developed. Ask: Are
there some areas where construction is not advisable no matter what the
building materials? Instruct students to add these notations to the maps.
3. When all the maps have been completed, site hazards have been
noted, and construction recommendations have been made, regroup
students into three or four large groups. Within each large group, stu-
dents can quiz each other about the potential of various sites on their
maps.
4. Ask for a volunteer from each large group to report on the group’s
findings and recommendations. Ask students: What would be the best
way to share your recommendations if these maps represented your
own area of the country?
C. Conclusion
Stack the three specialized maps on the projector at the same time so
the various kinds of information are all displayed simultaneously.
Discuss the conclusions that students have drawn and answer any
questions. Extend the discussion to the geologic history and hazard
potential of your own region.
(optional but highly recommended)
Direct students’ attention to the local map they prepared in Unit 1.
Have them follow the process they used above to transfer information
from local soil maps to the classroom map, noting any implications for
building and the location of critical facilities. If this process arouses
concerns about safety during an earthquake, ask students to contact the
local officials they interviewed in Unit 1 to express their concerns and
find out if these concerns have been taken into consideration. Ask these
students to report back to the class on what they learn.
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