s zion national park geologic-hazard study area ... · zion national park geologic-hazard study...
TRANSCRIPT
!
!
!
!
!
!
!
!
!
!
!
!!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
! !
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
18
19
31
30
07
31
30
19
06
18 17 16 15 14 13
04 03 02 01
18
06
31
11
30
31
19
07
18
06
06
07
08
20
16
06
05
29
32
05
09 12 0710
06
01
01
04 02
0908
01
11
11 11
10
11
11
11
11
11
0406
11
11
030203 0104 01
20
17
33
02
29
28
01
28
21
05
05
07
02
31
18
30
19
0603
34
04
27
21 24
35
12
26
28
21
31
22
13
23
13
30
04
18
22
31
29
20
14
32
25
32
01
32
33
28
12
36
14
20
31
26
15
21
27
22
33
31
28
23
34
09
16
09
23
35
28
33
13
14
13
33
17
12
24
27 25
15
10
34
15
12
26
22
25
10
22
29
35
28
27
27
34
34
26
36
35
34
36
08
33
27
36
16
27
09
16
14
14
23
27
09
26
33
36
29
25
23
31
26
22
32
24
16
10
01
21
23
35
20
13
07
30
17
19
25
08
10
28 3025
21
15
17
26
36
09
28
24
36
24
13
24
23
35
21
31
25
07
22 23
30
28
02
25
36
35
17
15
31
26
23
25
26
22
29
35
09
14
15
22
35
10
12
20
02
19
12
13
34
18
18
27
08
36
36
12
10
12
07
01
19
12
33
33
20
12
32
34
21
30
24
29
13
24
12
32
1818
25
19
05
20
36
07
34
13
25
35
14
07
36
33
08
26
07
09
03
21
01
02
19
07
21
30
09
04
14
12
16
16
03
10
18
25
24
08
03
10
35
04
19
31
29
13
34
02
33
28
20
10
35
15
24
2728
1417
03
34
24
21
23
26
32
22
09
19
2627
16
09
06
15
02
16
17
14
15
23
04
06
03
19
21
30
23
07
18
08
36
29
35
06
22
05
10
36
0405
34
20
06
32
29
17
20
08
32
05
30
05
33
0203 01 0604
27
34
22
05
13
19
08
11
31
11
25
24
17
20
18
31
19
30
07
29
32
01
10
17
15
08
06
05
1209
20
05
30 29 28 27 26 25 30
26
35
23
14
11
02
32
29
20
17
08
05
32
05
17
08
16
17
15
20
13
29
14
08
32
18 17
20
29
32
17
07
29
1108
08
09 10
08
12
05
1813141516171818 1314151613 17141516 17
COLLAPSIBLE-SOIL SUSCEPTIBILITYZION NATIONAL PARK GEOLOGIC-HAZARD STUDY AREA
EXPLANATION
T 38 ST 39 S
37 30'
113 7' 30"
2010
DISCUSSION
USING THIS MAP
SYMBOLS
ByWilliam R. Lund, Tyler R. Knudsen, and David L. Sharrow
Plate 6Utah Geological Survey Special Study 133
Zion National Park Geologic-Hazard Study Area, Washington and Kane Counties, Utah
Camp
Creek
Creek
Horse RanchMountain
Taylor Fork
North
Fork
Middle
Fork
South
LeePass
NaguntMesa
BuckPastureMountain
Creek
Timber
Kolob
CanyonsRoad
ShuntaviButte
GregoryButte
KolobArch Langston
Mountain
Creek
La Verkin
WillisCreek
BEAR CANYONTRAP
KO
LO
B
CA
NY
ON
S
BurntMountain
HO P
VA L L E Y
FirepitKnoll
PineValleyPeak
NorthgatePeaks
NorthGuardian
Angel
SouthGuardianAngel
Kolob
Terrac
eRo
ad
Kolob
Terrace
Road
North
Creek
Right
Fork
Left
Fork
Blue
Creek
Goose
Creek
LavaPoint
Kolob
Creek
DeepCr
eek
Coalp
itsWa
sh
Wash
Scoggins
Altar ofSacrifice
The WestTemple
MeridianTower The
Sentinel
MountKinesava
Wash
Hube
r
Creek
Oak
The Watchman
JohnsonMountain FORK
EAST
RIVER
VIRGIN
P A R U N U W E A P
C A N Y O N
BridgeMountain
The EastTemple
MountSpry
CraterHill
TwinBrothers
Mountainof the Sun
The GreatArch
The GreatWhite Throne
LadyMountain
CastleDome
Mount
AngelsLanding
ObservationPoint
Mountainof Mystery
WynopitsMountain
IvinsMountain
Timber
HU
RR
I CA
NE
CL I
FF
S
Death Point
Tucupit Point
Paria Point
Beatty Point
Top
Mountain
Herbs
Po
intLA
NGST
ON
CANYO
N
Currant
Creek
Cane
Creek
POLE
CANYON
L OW
E R
K OL O
B
P L A T E A U
UP P E R
K OL O
B
P L A T E A U
HO
RS
EP A
ST
UR
E
PL A
TE
AU
ZI O
N
CA
NY
ON
O R D E R V I L L E C A N Y O N
TheSubway
GREAT
WEST
CANYON
COUG
A R MO U N TA I N
CourtPatriarchsTheof
CreekBirch
Creek
Pine
Creek
Pine
Creek
Clear
Chec
kerbo
ard
Mes
a
Creek
Clear Creek
Co-op
GIFFORDCANYON
FORK
NORTH
RIVE
R
VIRGIN
ZION-MOUNT CARMEL TU NN EL
TUNNEL
Wash
Terry Wash
Jennin
gs
Wash
Coalpits
TheBishopric
HEAPS
CANYON
ECHO
CANYON
CableMountain
Temple ofSinawava
TELEPHONE
CANYON
IMLAY
CANYON
BULLOCH
GULC
HT H E
N A R R OWS
FORK
NORT
H
RIVER
VIRGIN
WILDCAT
CANYON
RUSSELLGULCH
North
Creek
North
Creek
Zion
Cany
on
Scen
icDr
ive
9
9
The Grotto
Zion CanyonVisitor Center
ZionLodge
Little
Creek
Grapevine
Wash
TOW
E RS
V I R G I NT H E
O F
Abraham Isaac
Jacob
ChurchMesa
PHANTOM VALLEY
CORRAL
HOLLOW
KolobCreek
WeepingRock
Cathedral Mountain
Majestic
Kolob CanyonsVisitor Center
WASH
INGT
ON C
OKA
NE C
O
IRON COWASHINGTON CO
Neag
le R
idge
BullpenMountain
Pocket Mesa
OAK SPRING VALLEY
PINE
VALLEYLEE
VALLEY
CaveKnoll
CAVE
VALLEY
TabernacleDome
Wash
SpringPine
TRAIL
CANYONGrea
theart
Mesa
BEHUNIN
CANYON
Creek
Shunes
Shunesburg Mountain
Wash
Hepworth
Wash
DennettCanyon
Bee HivePeak
HIDDENCANYON
CANYON
MYSTERY
R 12 W R 11 W
T 38 ST 39 S
R 11 W R 10 W
T 40 ST 41 S
T 41 ST 42 S
T 39 ST 40 S
T 41 ST 42 S
T 39 ST 40 S
T 40 ST 40.5 S
T 41 ST 42 S
R 11 W R 10 W
R 10 W
R 12 W R 11 W
R 10 W R 9.5 W R 9.5 W R 9 W
37 27' 30"
37 25'
37 22' 30"
37 20'
37 17' 30"
37 15'
37 12' 30"
37 10' 37 10'
37 12' 30"
37 15'
37 17' 30"
37 20'
37 22' 30"37 22' 30"
37 25'
113 5'
113 2' 30"
113
37 22' 30"
112 57' 30" 112 55'
112 52' 30"
112 52' 30"
112 55'112 57' 30"
113
113 2' 30"113 5'
113 7' 30"
113 10'
113 12' 30"
113 12' 30"
Zion National Park Geologic-Hazard Study Area boundaryZion National Park boundaryCounty boundaryState highwayMinor roadFoot trailExisting park structureArea not studied
37 27' 30"
MAP LIMITATIONSThis map is based on limited geologic and geotechnical data; site-specific investigations are required to producemore detailed geotechnical information. The map also depends on the quality of those data, which may varythroughout the study area. The mapped boundaries between susceptibility categories are approximate andsubject to change as new information becomes available. The susceptibility may be different than shown at anyparticular site because of variations in the physical properties of geologic deposits within a map unit, gradationaland approximate map-unit boundaries, and the small map scale. The map is not intended for use at scales otherthan the published scale, and is designed for use in general planning and design to indicate the need for site-specific investigations.
This map shows the location of known and suspected collapsible-soil conditions in the Zion National ParkGeologic-Hazard Study Area. The map is intended for general planning and design purposes to indicate wherecollapsible-soil conditions may exist and special investigations should be required. Site-specific investigationscan resolve uncertainties inherent in generalized mapping and help identify the need for special design, sitegrading and soil placement, and/or mitigation techniques. The presence and severity of collapsible soil alongwith other geologic hazards should be addressed in these investigations. If collapsible soil is present at a site,appropriate design and construction recommendations should be provided.
HAZARD REDUCTIONAlthough potentially costly when not recognized and properly accommodated in project design and construction,problems associated with collapsible soil rarely are life threatening. As with most geologic hazards, earlyrecognition and avoidance are the most effective ways to mitigate potential problems. However, collapsible soilis widespread in the study area, and avoidance may not always be a viable or cost-effective option.In Utah, soil-test requirements are specified in chapter 18 (Soils and Foundations) of the 2009 InternationalBuilding Code (IBC) (International Code Council, 2009a) and chapter 4 (Foundations) of the 2009 InternationalResidential Code for One- and Two-Family Dwellings (IRC) (International Code Council, 2009b), which areadopted statewide. IBC Section 1803.3 contains requirements for soil investigations in areas where questionablesoil (soil classification, strength, or compressibility) is present. IRC Section R401.4 states that the building officialshall determine whether to require a soil test to determine the soil’s characteristics in areas likely to haveexpansive, compressible, shifting, or other unknown soil characteristics. IBC table 1613.5.2 identifies collapse-prone soils as Site Class F. Site Class F soils require a site-specific investigation to determine the proper seismicdesign category and parameters for a proposed facility (see chapter 5 – Earthquake Hazards in accompanyingtext).Where the presence of collapsible soil is confirmed, possible mitigation techniques include soil removal andreplacement with noncohesive, compacted backfill; use of special foundation designs such as drilled pier deepfoundations, grade beam foundations, or stiffened slab-on-grade construction; moisture barriers; and careful sitelandscape and drainage design to keep moisture away from buildings and collapse-prone soils (Nelson andMiller, 1992; Pawlak, 1998; Keller and Blodgett, 2006).
UTAH GEOLOGICAL SURVEYa division of Utah Department of Natural Resourcesin cooperation withNational Park Service
This geologic-hazard map was funded by the Utah Geological Survey and theU.S. Department of the Interior, National Park Service. The views andconclusions contained in this document are those of the authors and should notbe interpreted as necessarily representing the official policies, either expressedor implied, of the U.S. Government.Although this product represents the work of professional scientists, the UtahDepartment of Natural Resources, Utah Geological Survey, makes no warranty,expressed or implied, regarding its suitability for a particular use. The UtahDepartment of Natural Resources, Utah Geological Survey, shall not be liableunder any circumstances for any direct, indirect, special, incidental, orconsequential damages with respect to claims by users of this product.For use at 1:24,000 scale only. The Utah Geological Survey does notguarantee accuracy or completeness of data.
www.geology.utah.gov
Base map consists of U.S. Department of Agriculture 2006 National AgriculturalImagery Program natural color aerial photography and shaded relief generatedfrom digital elevation data acquired from the Utah Automated GeographicReference Center.
Universal Transverse Mercator Projection, zone 12North American Datum of 1983
Unconsolidated geologic units with reported collapse values of >3 percent.
Geologically young (Holocene) unconsolidated geologic units with no available geotechnical data, butwhose genesis or texture is permissive of collapse (chiefly geologically young alluvial, colluvial, andeolian deposits).
Older unconsolidated geologic units (Pleistocene) with no available geotechnical data, but likecategory CSB have a genesis or texture permissive of collapse. Because of their age, these depositshave had greater exposure to natural wetting and collapse may have occurred, and/or the depositsmay be cemented by secondary calcium carbonate or other soluble minerals.
Geologic Deposits Known or Likely to Have a Significant Potential for Soil Collapse
Type ofDeposit
Collapsible SoilCategory
Stream andTerraceAlluvium
LacustrineDeposits
FanAlluvium
Eolian Deposits
Qa1, Qal1, Qat2, Qat3, Qath
1Refer to UGS geologic quadrangle maps (see Sources of Information and References in accompanyingtext) for descriptions of map units.
Qa, Qaly, Qay, Qa2, Qat4, Qat5, Qat6, Qas, QasoQato, Qav
Qafc, Qafco, Qmsc (alluvial parts)Qae, Qac, Qaes, Qaeo, Qaf, Qaf1, Qaf2, Qafy,
Qao, Qafo, Qage, Qmcp1, Qmcp2 Qaco, Qaec, Qap2, Qmcp3
Qea, Qer, Qes, Qed, Qre
ColluvialDeposits
Qc, Qmt, Qmts, Qce, QcesQco
Qla, QlsQlbc
Map Units1
CSA
CSB
CSC
CSA
CSB
CSC
CSB
CSB
CSC
CSB
CSC
Approximate meandeclination, 2009
12 9'o
TRUE
NOR
THMA
GNET
IC N
ORTH
Map Location
1 0 10.5 MILE
1000 0 1000 2000 3000 4000 5000 6000 7000 FEET1 0 10.5 KILOMETER
SCALE 1:24,000
CSA
CSB
CSC
Collapsible (hydrocompactible) soils have considerable dry strength and stiffness in their dry natural state, butcan settle up to 10 percent of the susceptible deposit thickness when they become wet for the first time followingdeposition (Costa and Baker, 1981; Rollins and Rogers, 1994) causing damage to property and structures.Collapsible soils are common throughout the arid southwestern United States and are typically geologicallyyoung materials, chiefly debris-flow deposits in Holocene-age alluvial fans, and some wind-blown, lacustrine, andcolluvial deposits (Owens and Rollins, 1990; Mulvey, 1992; Santi, 2005).Collapsible soils typically have a high void ratio and corresponding low unit weight (<80 to 90 lb/ft ; Costa andBaker, 1981; Walter Jones, consulting engineer, written communication, 2007) and a relatively low moisturecontent (<15%; Owens and Rollins, 1990), all characteristics that result from the initial rapid deposition anddrying of the sediments. Intergranular bonds form between the larger grains (sand and gravel) of a collapsiblesoil; these bonds develop through capillary tension or a binding agent such as silt, clay, or salt. Later wetting ofthe soil results in a loss of capillary tension or the softening, weakening, or dissolving of the bonding agent,allowing the larger particles to slip past one another into a denser structure (Williams and Rollins, 1991).In general, collapsible alluvial-fan and colluvial soils are associated with drainage basins that are dominated bysoft, clay-rich sedimentary rocks such as shale, mudstone, claystone, and siltstone (Bull, 1964; Owens andRollins, 1990). Bull (1964) found that the maximum collapse of alluvial-fan soils in Fresno County, California,coincided with a clay content of approximately 12 percent. Alluvial-fan deposits exhibiting dramatic collapsebehavior in Nephi, Utah, typically contained 10 to 15 percent clay-size material (Rollins and Rogers, 1994). Atclay contents greater than about 12 to 15 percent, the expansive nature of the clay begins to dominate and thesoil is subject to swell rather than collapse. Characteristically, collapsible soils consist chiefly of silty sands,sandy silts, and clayey sands (Williams and Rollins, 1991), although Rollins and others (1994) identified collapse-prone gravels containing as little as 5 to 20 percent fines at several locations in the southwestern United States.Soil composition is the primary indicator of collapse potential in alluvial-fan and colluvial soils. However, alongthe southern Wasatch Front, Owens and Rollins (1990) found that the degree of collapse generally increasedwith an increase in the ratio of fan area to drainage-basin area. In other words, alluvial fans (especially largealluvial fans) associated with small drainage basins had a greater likelihood of producing collapse-prone soils.Bull (1964) found a similar relation between fan and drainage-basin size in Fresno County.Loess—deposits of wind-blown clay, silt, and fine sand—typically has an extremely loose, open structure that ismaintained by water-soluble mineral cements or high-plasticity clay that act as a binder between larger grains(Gibbs and Holland, 1960; Costa and Baker, 1981). Like collapse-prone alluvial-fan soils, undisturbed loesstypically has a high void ratio, a correspondingly low in-place density, and is relatively dry. When wetted, loesswill collapse; the extent of the collapse largely depends on the texture (grain-size distribution) of the deposit.Gibbs and Holland (1960) found that clay-rich loess deposits tend to collapse less than those containing a higherpercentage of silt and fine sand.Naturally occurring deep percolation of water into collapsible deposits is uncommon after deposition due to thearid conditions in which the deposits typically form, and the steep gradient of many alluvial-fan and colluvialsurfaces. Therefore, soil collapse is usually triggered by human activity such as irrigation, urbanization, and/orwastewater disposal. Kaliser (1978) reported serious damage (estimated $3 million) to public and privatestructures in Cedar City, Utah, from collapsible soils. Rollins and others (1994) documented more than $20million in required remedial measures to a cement plant near Leamington, Utah, and Smith and Deal (1988)reported damage to a large flood-control structure near Monroe, Utah. In 2001, collapsible soils damaged theZion National Park greenhouse soon after it was constructed, as soils below and around the building were wettedby excess irrigation water. Park employees later reported that a wastewater treatment plant that had once beenlocated nearby had also had a history of damage from ground subsidence. Damage due to collapse of wind-blown deposits is not as well documented in Utah as damage associated with collapsible alluvial and colluvialdeposits; this may be due in part to the relatively lesser abundance of loess deposits in the state.For additional information about collapsible soil in the Zion National Park Geologic-Hazard Study Area, refer tothe Problem Soil and Rock Hazards chapter in this report.
3
REFERENCES
Survey Professional Paper 437-A, 70 p.
p.
Reclamation Engineering Monograph No. 28, 37 p.
Hills, Illinois, 870 p.
of Investigation 124, 130 p.
catastrophes: Upper Saddle River, New Jersey, Pearson Prentice Hall, 395 p.
Special Study 80, 23 p., 2 plates, scale 1:500,000.
engineering: New York, John Wiley & Sons, 259 p.
Geological and Mineral Survey Miscellaneous Publication 90-1, 38 p.
Colorado: Online, HP-Geotech, SLP paper, 4 p., <http://www.hpgeotech.com/Steve_Paper.htm >, accessedMay 4, 2008.
Journal of Geotechnical Engineering, v. 120, no. 9, p. 1533-1553.
collapsible gravels: Journal of Geotechnical Engineering, v. 120, no. 3, p. 528-542.
patterns [abs.]: Geological Society of America Abstracts with Programs, v. 37, no. 7, p. 326.
Proceedings 2 International Conference on Case Histories in Geotechnical Engineering, St. Louis, Missouri:University of Missouri at Rolla, p. 451-455.
Survey Contract Report 91-10, 44 p.
Bull, W.B., 1964, Alluvial fans and near-surface subsidence in western Fresno County, California: U.S. Geological
Costa, J.E., and Baker, V.R., 1981, Surficial geology, building with the earth: New York, John Wiley & Sons, 498
Gibbs, H.J., and Holland, W.Y., 1960, Petrographic and engineering properties of loess: U.S. Bureau of
International Code Council, 2009a, International building code: Country Club Hills, Illinois, 678 p.International Code Council, 2009b, International residential code for one- and two-family dwellings: Country Club
Kaliser, B.N., 1978, Ground surface subsidence in Cedar City, Utah: Utah Geological and Mineral Survey Report
Keller, E.A., and Blodgett, R.H., 2006, Natural hazards – Earth’s processes as hazards, disasters, and
Mulvey, W.E., 1992, Soil and rock causing engineering geologic problems in Utah: Utah Geological Survey
Nelson, J.D., and Miller, D.J., 1992, Expansive soils, problems and practice in foundation and pavement
Owens, R.L., and Rollins, K.M., 1990, Collapsible soil hazard map for the southern Wasatch Front, Utah: Utah
Pawlak, S.L., 1998, Evaluation, design, and mitigation of project sites in collapsible soil areas in western
Rollins, K.M., and Rogers, G.W., 1994, Mitigation measures for small structures on collapsible alluvial soils:
Rollins, K.M., Rollins, R.L., Smith, T.D., and Beckwith, G.H., 1994, Identification and characterization of
Santi, P., 2005, Recognition of collapsible soils based on geology, climate, laboratory tests, and structural crack
Smith, T.D., and Deal, C.E., 1988, Cracking studies at the Sand-H basin by the finite element method,
Williams, T., and Rollins, K.M., 1991, Collapsible soil hazard map for Cedar City, Utah area: Utah Geological
innd