Earthquake Awareness Assignment (Scenario Assignment 1)
Due Feb 10
Objectives
 Able to read a fault map so as to establish proximity to known faults
http://www.consrv.ca.gov/CGS/rghm/psha/fault_parameters/htm/Pages/index.aspx
 Able to comprehend that some faults are not known or mapped – an area may be seismically
active…
 Able to understand that some substrates amplify shaking, others do not
 Able to assess type of construction and thus safety of a structure
 Able to comprehend likelihood of liquefaction
Scenario: You are considering purchase of a house in several neighborhoods around Hayward,
California. You have received a booklet from your realtor called “Putting Down Roots in Earthquake
Country” and you know something about the impact of earthquakes on buildings, and the responses of
buildings to earthquakes. You have also found out that the Hayward Fault ruptured in 1868 and could be
considered ‘overdue’ for another serious movement today. In each neighborhood you have a choice of
homes, with different construction styles. Assume that each is well built according to that style. You are
preparing materials with which to compare these and make a decision. Money is not the object; longterm safety is.
Instructions
 Go to http://www.arcgis.com/home/
Search for GEOG 240 Scenario Exercise 1 – click OPEN – map should appear.
If you are not already centered on San Francisco Bay, type “Hayward, CA” into the ‘Find address or
place’ box. X away that address box. Zoom in to the area just north of the label – you’ll see Cal State
Univ East Bay.
This map shows earthquake faults – click once on any fault line, you get information: Name, age, rate of
movement, slip sense & direction (what type/direction of fault, if known).
It also shows FIVE push-pin symbols west and north of Cal State Univ East Bay (click the bottom of the
pin to see letter & street name).
o
o
o
o
o
Location A is on Virginia Street just west of Holy Sepulchre Cemetery.
Location B is to the west, west of Southland Mall on Mobile in the Hayward/Mobile/Country
Club neighborhood.
Location C is a mile south and a little further west, on Whitesell Street off 92.
Location D is further north up the coastline – on Driftwood Way, east of Marina Park (just south
east of Oakland International Airport)
Location E is almost due north almost 5 miles, on Seneca Street, just north of Seneca Reservoir
in the hills near King Estate Recreation Area and the zoo.
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As you explore the map, note the Legend icon: click that and you’ll see what colors on the fault lines
mean. You may need to click on ‘Details’ first.
Click on the CONTENTS icon: you will see several layers – Landslides and Liquefaction are two layers
that are currently not checked. Check them – and two dark layers appear over parts of the map. Since
they cover the streets, you will need to turn them off and on to see where they are important.
Likelihood of liquefaction and landslide in the areas shown is not provided by the data source
(http://atlas.resources.ca.gov/ArcGIS/rest/services/GeoScience/HazardMaps_09_01_2009_Seismic/Ma
pServer) – so assume that they are possible, but not guaranteed.
Open a new tab on your internet browser. Go to http://earthquake.usgs.gov/regional/nca/soiltype/
(Soil Type and Shaking Hazard in the San Francisco Bay Area, with interactive map - USGS, no date). Click
on the ‘interactive map’ – the explanation for its legend is below. There is no search function on this
map! You need to zoom in to San Francisco, look for Oakland International Airport on the east side of
the bay, and move west & south. You can make out major roads and street patterns. I have tried to
choose locations that are obvious based on these features. On this map, you are looking at COLOR and
thus substrate type to assess how shaking would be amplified – or not – in each of the five locations.
Legend (bottom of map) associates color with letter, and thus with Map Legend below.
For each of the five locations, fill out the boxes on the 2 worksheets by looking at the maps and
reading about building styles, below. You will need to read about the impacts of earthquakes, and the
responses of buildings to earthquakes.
Finally, select one construction style in one neighborhood; write a paragraph justifying your
explanation.
Background information (PDFs or links available on Canvas and Hazards Blog):
The Hayward Fault—Is It Due for a Repeat of the Powerful 1868 Earthquake? (Brocher, T.M., J.
Boatwright, J.J. Lienkaemper, C.S. Prentice, D.P. Schwartz, & H. Bundock, 2008. USGS Fact Sheet
2008-3019, http://pubs.usgs.gov/fs/2008/3019/)
Putting Down Roots in Earthquake Country: Your Handbook for the San Francisco Bay Region (USGS,
General Information Product 15, http://pubs.usgs.gov/gip/2005/15/)
Guide to Housing Vulnerable to Earthquakes (Association of Bay Area Governments, Earthquake and
Hazards Program, 2012) http://quake.abag.ca.gov/housing/
Earthquake Shaking and Building Response (Building Safety & Earthquakes, Briefing Paper 1 Applied
Technology Council (ATC) and the Structural Engineers Association of California (SEAOC) Joint
Venture, no date) http://www.atcouncil.org/pdfs/bp1a.pdf
How Earthquakes Affect Buildings (MCEER Information Service, SUNY Buffalo, 2010)
http://mceer.buffalo.edu/infoservice/reference_services/EQaffectBuilding.asp
How Buildings Respond to Earthquakes (MCEER Information Service, SUNY Buffalo, 2010)
http://mceer.buffalo.edu/infoservice/reference_services/buildingRespondEQ.asp
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Map Legend:
Shear wave velocity
NEHRP
(Vs) [shaking is
Soil
amplified where Vs is
type
lower]
Description
Includes unweathered intrusive igneous rock. Occurs infrequently in the bay
area. We consider it with type B (both A and B are represented by the color
Vs > 1500 m/sec
blue on the map). Soil types A and B do not contribute greatly to shaking
amplification.
Includes volcanics, most Mesozoic bedrock, and some Franciscan bedrock.
B
1500 m/sec > Vs >
(Mesozoic rocks are between 245 and 64 million years old. The Franciscan
Blue
750 m/sec
Complex is a Mesozoic unit that is common in the Bay Area.)
Includes some Quaternary (less than 1.8 million years old) sands, sandstones
C
750 m/sec > Vs > 350 and mudstones, some Upper Tertiary (1.8 to 24 million years old) sandstones,
Green m/sec
mudstones and limestone, some Lower Tertiary (24 to 64 million years old)
mudstones and sandstones, and Franciscan melange and serpentinite.
D
350 m/sec > Vs > 200 Includes some Quaternary muds, sands, gravels, silts and mud. Significant
Yellow m/sec
amplification of shaking by these soils is generally expected.
E
Includes water-saturated mud and artificial fill. The strongest amplification of
200 m/sec > Vs
Pink
shaking due is expected for this soil type.
NEHRP = National Earthquake Hazard Reduction Program
A
Blue
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Summary of the response of construction styles to earthquakes
Frame Type
Wood
Structures
Structure Type
Description
Pre-1949 - not always connected to
foundation
Post 1949, standard wood frame walls with 2x4” or
2x6” wood studs, spaced 16" apart. Outside covering
is stucco, lap sizing or plywood. Inside covering is
gypsum board or lath & plaster. Resistant to
earthquakes if bolted to foundation.
Post-1949 - bolted to foundation
Frame is of steel, with concrete block exterior and
interior walls. Somewhat resistant.
Steel moment resisting frames are braced or trussed
by having diagonals inserted within the frames, as
single or cross bracing; other kinds of bracing are
common, but concealed; all make structures resistant
to earthquake motion.
Both brick and concrete block; often over 100 years
old. Little or no embedded steel. Walls support
weight of building, doors, etc. Banned in CA after
1945. No earthquake protection
Concrete block, brick or stone; with steel bars
inserted into interior space, and space filled with
concrete. Bolted to foundation. Strong, but nonductile.
With concrete shear walls
Steel Frame
Moment resisting frame*
Unreinforced
Masonry
Reinforced
Concrete
Reinforced concrete frame, nonductile
Vertical columns and horizontal beams of cast
concrete, exposed or covered by masonry, typically
pre-1975 (but parking garage at CSU Northridge was
new 1994). Insufficiently reinforced through joints
and ties, ties widely spaced - so unable to deform
under stress; breaks during earth motion.
Reinforced concrete frame, ductile
As above but with closely spaced reinforcements.
Common after 1980; resistant.
Concrete moment resisting frames have reinforced
concrete shear walls, to support the vertical load,
surrounded by a metal frame - so combining the
flexibility of the frame with non-ductile interior walls.
E.g. apartment buildings & offices with a central
elevator core within a frame of rooms. Very resistant.
Moment resisting frame*
*Any moment resisting frame has horizontal columns and vertical beams (or girders) which are
interconnected and thus bear the weight of the building in a series of frames.
Based on:
http://www.icwgroup.com/agents/earthquake/documents/ICW-Group-ATC-Code-Guide-for-Risks.pdf
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