STATE OF OREGON Tsunami Inundation Map Coos-07 DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES Tsunami Inundation Maps for Coos River South www.OregonGeology.org Local Source (Cascadia Subduction Zone) Tsunami Inundation Map Coos County, Oregon Larry Givens, Governing Board Chair Vicki S. McConnell, Director and State Geologist Plate 1 Don W.T. Lewis, Assistant Director

Rachel R. Lyles Smith, Project Operations Manager Coos River South, Oregon Ian P. Madin, Chief Scientist 200 2012

124°10'0"W 124°8'0"W 124°6'0"W 124°4'0"W

100 Introduction 200 Oregon. DOGAMI has also incorporated physical evidence that suggests The Oregon Department of Geology and Mineral Industries (DOGAMI) 241 that portions of the coast may drop 4 to 10 feet during the earthquake; has been identifying and mapping the tsunami inundation hazard along E A S T B AY R D 25 200 the Oregon coast since 1994. In Oregon, DOGAMI manages the National this effect is known as subsidence. Detailed information on fault 100

Tsunami Hazard Mitigation Program, which has been administered by geometries, subsidence, computer models, and the methodology used to D R H T I RNDLA the National Oceanic and Atmospheric Administration (NOAA) since create the tsunami scenarios presented on this map can be found in 1995. DOGAMI’s work is designed to help cities, counties, and other DOGAMI Special Papers 41 (Priest and others, 2009) and 43 (Witter and

S & D R D sites in coastal areas reduce the potential for disastrous tsunami-related others, 2011).

consequences by understanding and mitigating this geologic hazard.

200 100 Using federal funding awarded by NOAA, DOGAMI has developed a C 25 Map Explanation Ci ty of Coo s Bay 241 oos new generation of tsunami inundation maps to help residents and Coos Ri R i This tsunami inundation map displays the output of computer models v v visitors along the entire Oregon coast prepare for the next Cascadia er er S C O representing five selected tsunami scenarios, all of which include the O S R I V E Subduction Zone (CSZ) earthquake and tsunami. R L N earthquake-produced subsidence and the tsunami-amplifying effects of The CSZ is the tectonic plate boundary between the North American the splay fault. Each scenario assumes that a tsunami occurs at Mean Plate and the Juan de Fuca Plate (Figure 1). These plates are converging Higher High Water (MHHW) tide; MHHW is defined as the average height at a rate of about 1.5 inches per year, but the movement is not smooth of the higher high tides observed over an 18-year period at the Port BRUNSWICK LN and continuous. Rather, the plates lock in place, and unreleased energy Orford tide gauge. To make it easier to understand this scientific material ECHO SPRING LN

25 and to enhance the educational aspects of hazard mitigation and 100 S O LA R I R D builds over time. At intervals, this accumulated energy is violently 200 S C O O S response, the five scenarios are labeled as “T-shirt sizes” ranging from R released in the form of a megathrust earthquake rupture, where the I V E R L N North American Plate suddenly slips westward over the Juan de Fuca Small, Medium, Large, Extra Large, to Extra Extra Large (S, M, L, XL, XXL). TIMBER PARK LN

The map legend depicts the respective amounts of slip, the frequency of N Plate. This rupture causes a vertical displacement of water that creates L R E occurrence, and the earthquake magnitude for these five scenarios. I V a tsunami (Figure 2). Similar rupture processes and tsunamis have R S O Figure 4 shows the cumulative number of buildings inundated within the O occurred elsewhere on the planet where subduction zones exist: for C S example, offshore Chile in 1960 and 2010, offshore Alaska in 1964, near map area. 25

Sumatra in 2004, and offshore Japan in March 2011. 100

The computer simulation model output is provided to DOGAMI as 200 43°22'0"N CSZ Frequency: Comprehensive research of the offshore geologic millions of points with values that indicate whether the location of each point is wet or dry. These points are converted to wet and dry contour

record indicates that at least 19 major ruptures of the full length of the 100 13 25 lines that form the extent of inundation. The transition area between the 100 CSZ have occurred off the Oregon coast over the past 10,000 years R R D 25 R I V E O O S

wet and dry contour lines is termed the Wet/Dry Zone, which equates to C 200 (Figure 3). All 19 of these full-rupture CSZ events were likely magnitude SUNSHINE RD the amount of error in the model when determining the maximum C E D A R D R 8.9 to 9.2 earthquakes (Witter and others, 2011). The most recent CSZ D 241 R inundation for the each scenario. Only the XXL Wet/Dry Zone is shown on T H event happened approximately 300 years ago on January 26, 1700. R I N D L A

Sand deposits carried onshore and left by the 1700 event have been this map. 25 1 6 T H A V E L I L L I A N S L O U G H L N

found 1.2 miles inland; older tsunami sand deposits have also been

100

25 R

200

43°22'0"N This map also shows the regulatory tsunami inundation line (Oregon O

discovered in estuaries 6 miles inland. As shown in Figure 3, the range 100

S 200 S

Revised Statutes 455.446 and 455.447), commonly known as the Senate

in time between these 19 events varies from 110 to 1,150 years, with a I D

200 N 100 R

L

Bill 379 line. Senate Bill 379 (1995) instructed DOGAMI to establish the E 25

H median time interval of 490 years. In 2008 the United States Geological T

G

U area of expected tsunami inundation based on scientific evidence and R Survey (USGS) released the results of a study announcing that the D O S T L I A

S N S

M 25 tsunami modeling in order to prohibit the construction of new essential I T H

probability of a magnitude 8-9 CSZ earthquake occurring over the next G L N 100 Ci ty of Coo s Bay N and special occupancy structures in this tsunami inundation zone (Priest, I H 100 30 years is 10% and that such earthquakes occur about every 500 200

25

C 200

T

1995). A

years (WGCEP, 2008). C 100

D 200 R Time Series Graphs and Wave Elevation Profiles: In addition to the CSZ Model Specifications: The sizes of the earthquake and its resultant K E E tsunami scenarios, the computer model produces time series data for R C S tsunami are primarily driven by the amount and geometry of the slip S C L O E O “gauge” locations in the area. These points are simulated gauge stations I S that takes place when the North American Plate snaps westward over N R A I

D V E that record the time, in seconds, of the tsunami wave arrival and the wave 25 R the Juan de Fuca Plate during a CSZ event. DOGAMI has modeled a wide S I G L U N L N L N range of earthquake and tsunami sizes that take into account different height observed. It is especially noteworthy that the greatest wave height and velocity observed are not necessarily associated with the first fault geometries that could amplify the amount of seawater k e tsunami wave to arrive onshore. Therefore evacuees should not assume e

displacement and increase tsunami inundation. Seismic geophysical r that the tsunami event is over until the proper authorities have sounded C 100 profiles show that there may be a steep splay fault running nearly Catching Slough h the all-clear signal at the end of the evacuation. Figure 5 depicts the t parallel to the CSZ but closer to the Oregon coastline (Figure 1). The i tsunami waves as they arrive at a simulated gauge station. Figure 6 m effect of this splay fault moving during a full-rupture CSZ event would S

depicts the overall wave height and inundation extent for all five scenarios be an increase in the amount of vertical displacement of the Pacific G A R F I E L D L N 200 Ocean, resulting in an increase of the tsunami inundation onshore in at the profile locations shown on this map. South Fork Coos River

A L N

I S K

K 25

25

Cascadia Subduction Zone Setting 100 200

A G U N N E L L L N A' 100

N

L

H

T

0

2

25

200

100 200

D

R

T T

E

L

N

I S S 100 S O

R

W C A T C H IN G R D 25

100

200 200

200

S C O V 100 I L L E L N

Figure 1: This block diagram depicts the tectonic setting of the region. See Figure 2 for the sequence of DANIELS CREEK RD events that occur during a Cascadia Subduction Zone megathrust earthquake and tsunami.

Y RD R AY W K R A P R D D G E R I M E O U R B L G A N

How Tsunamis Occur C R E E K

L N

C O L LV E R L N

B M O R G A N L N 100

200

25

100

100 200

A B C

100

Figure 2: The North American Plate rides Because the two plates are stuck in place at Eventually the locked zone ruptures and 100 200

43°20'0"N over the descending Juan de Fuca Plate at a the “locked zone,” strain builds up over time causes a great earthquake. The sudden slip of 200 rate of approximately 1.5 inches per year. and the North American Plate bulges up. the two plates displaces Pacific Ocean water

upward and creates a tsunami. 200

D S T O C K S L O U G H L N 200

R 100

G

N

I

H

C

T C A O L L C V

E

25 R L N

200 W 100

D

A 200 N

100 I E

L

S

C 43°20'0"N 25 R

E T R Y L N E U N K C O E D R D

C Displaced and uplifted Pacific Ocean water Along the Oregon coast, tsunami waves run A T rushes in all directions. up onto the land for several hours. C H

I

N

100

G

S

L

O 200

Occurrence and Relative Size of Cascadia Subduction Zone Megathrust Earthquakes U

G

H

R Figure 3: This chart depicts the timing, D frequency, and magnitude of the last 19 great Cascadia Subduction Zone events over the SHELLHAMER RD

past 10,000 years. The most recent event C a occurred on January 26, 1700. The 1700 t c event is considered to be a “medium sized” h i W R E N S M I T H L N n event. The data used to create this chart came g B' from research that examined the many S l o

submarine landslides, known as “turbidites,” u

g

that are triggered only by these great h

earthquakes (Witter and others, 2011). The A N C H O R R D loose correlation is “the bigger the turbidite,

the bigger the earthquake.” 25

100 200

Buildings within Tsunami Inundation Zones O L D W A G O N R D

OLD SAWMILL RD

100 200

124°10'0"W 124°8'0"W 124°6'0"W 124°4'0"W 124°2'0"W

Estimated Tsunami Wave Height through Time for Simulated Gauge Station Maximum Wave Elevation Profiles Tsunami Inundation Map Index Legend Data References Source Data: References: Average Slip Maximum Slip Time to Earthquake This map is based on hydrodynamic tsunami modeling by 2007 Working Group on California Earthquake Joseph Zhang, Oregon Health and Science University, Probabilities (WGCEP), 2008, The Uniform California Earthquake Size Range (ft) Range (ft) Accumulate Slip (yrs) Magnitude Portland, Oregon. Model data input were created by John Earthquake Rupture Forecast, Version 2 (UCERF 2): U.S. T. English and George R. Priest, Department of Geology Geological Survey Open-File Report 2007-1437 and 01 02 XXL 59 to 72 118 to 144 1,200 ~9.1 and Mineral Industries (DOGAMI), Portland, Oregon. California Geological Survey Special Report 203 [http://pubs.usgs.gov/of/2007/1437/]. Hydrology data, contours, critical facilities, and building 03 XL 56 to 72 115 to 144 1,050 to 1,200 ~9.1 footprints were created by DOGAMI. Senate Bill 379 line Priest, G. R., 1995, Explanation of mapping methods and data were redigitized by Rachel R. Lyles Smith and Sean G. use of the tsunami hazard maps of the Oregon coast, 04 Pickner, DOGAMI, in 2011 (GIS file set, in press, 2012). Oregon Department of Geology and Mineral Industries L 36 to 49 72 to 98 650 to 800 ~9.0 Open-File Report O-95-67, 95 p. Urban growth boundaries (2010) were provided by the 06 Oregon Department of Land Conservation and Priest, G.R., Goldfinger, C., Wang, K., Witter, R.C., Zhang, Y., 05 M 23 to 30 46 to 62 425 to 525 ~8.9 Development (DLCD). and Baptista, A.M., 2009, Tsunami hazard assessment of s the northern Oregon coast: a multi-deterministic a s

l

07 o g Transportation data (2008) provided by Coos County approach tested at Cannon Beach, Clatsop County,

o u were edited by DOGAMI to improve the spatial accuracy Oregon: Oregon Department of Geology and Mineral C S 13 to 16 30 to 36 300 ~8.7 08 09 o 10 11 D of the features or to add newly constructed roads not Industries Special Paper 41, 87 p. present in the original data layer. XXL Wet/Dry Zone Witter, R.C., Zhang, Y., Wang, K., Priest, G.R., Goldfinger, C., Lidar data are from LDQ-2009-43124-C1-DanielsCreek, Stimely, L.L., English, J.T., and Ferro, P.A., 2011, Simulating 12 13 LDQ-2009-43124-C2-CoosBay, LDQ-2009-43124-D1- tsunami inundation at Bandon, Coos County, Oregon, 14 Allegany, and LDQ-2009-43124-D2-NorthBend. using hypothetical Cascadia and Alaska earthquake scenarios: Oregon Department of Geology and Mineral 15 Urban Growth Boundary Fire Station Coordinate System: Oregon Statewide Lambert Industries Special Paper 43, 57 p. Conformal Conic, Unit: International Feet, Horizontal 16 Datum: NAD 1983 HARN, Vertical Datum: NAVD 1988. Police Station Graticule shown with geographic coordinates OREGON Building Footprint (latitude/longitude). Figure 6: These profiles depict the expected maximum tsunami wave elevation for the five “tsunami T-shirt scenarios” along lines A-A' and B-B'. The tsunami scenarios are modeled to occur at high tide and to account for local subsidence or uplift of the ground 17 surface. Software: Esri ArcGIS® 10.0, Microsoft® Excel®, and 6 School Adobe® Illustrator® Coos Simulated Gauge Station Curry Funding: This map was funded under award Profile Location Hospital/Urgent Care Clinic #NA09NW54670014 by the National Oceanic and Atmospheric Administration (NOAA) through the National Tsunami Hazard Mitigation Program. Senate Bill 379 Line 101 Coos-01 Lakeside West Coos-10 Isthmus Slough U.S. Highway Map Data Creation/Development: Coos-02 Lakeside East Coos-11 Catching Slough Tsunami Inundation Scenarios: George R. Priest, Coos-03 Saunders Lake Coos-12 Bullards Beach State Park Laura L. Stimely, Daniel E. Coe, Paul A. Ferro, Coos-04 Haynes Inlet Coos-13 Leneve 241 State Highway Sean G. Pickner, Rachel R. Lyles Smith Figure 5: This chart depicts the tsunami waves as they arrive at the selected reference point (simulated gauge station). It shows the change in wave heights Basemap Data: Kaleena L.B. Hughes, Sean G. Pickner for all five tsunami scenarios over an 8-hour period. The starting water elevation (0.0 hour) takes into account the local land subsidence or uplift caused by Coos-05 Coos Bay - North Bend Coos-14 Coquille Coos-06 Coos River North Coos-15 Coquille River Elevation Contour the earthquake. Wave heights vary through time, and the first wave will not necessarily be the largest as waves interfere and reflect off local topography and Map Production: Coos-07 Coos-16 Bandon Improved Road bathymetry. Coos River South (25 ft intervals up to 200 ft) Cartography: Kaleena L.B. Hughes, Sean G. Pickner, Coos-08 Charleston - Cape Arago Coos-17 New River Taylore E. Womble Coos-09 Barview - South Slough Text: Don W.T. Lewis, Rachel R. Lyles Smith For copies of this publication contact: Nature of the Northwest Information Center 0 0.25 0.5 Mile Editing: Don W.T. Lewis, Rachel R. Lyles Smith Figure 4: The table and chart show the number of buildings inundated for each “tsunami T-shirt scenario” for 800 NE Oregon Street, #28, Ste. 965 Publication: Deborah A. Schueller Portland, Oregon 97232 cities and unincorporated portions of the map. Map Date: 07/19/2012 telephone (971) 673-2331 0 0.25 0.5 1 Kilometer Scale 1:12,000 http://www.naturenw.org