Rob Witter,
Regional Coastal Geologist,
Oregon Department of Geology and Mineral Industries, Coastal Field Office
313 SW 2nd, Suite D
Newport OR 97365
Phone: (541) 574-7969
Fax: (541) 265-5241

rob.witter@dogami.state.or.us


Current Projects

Erosion and Landslide Hazard Mapping for the Southern Lincoln County Coast, funded by Lincoln County, administered through the Department of Land Conservation and Development, Project Period: September 2005 to December 2006..

Paleoseismology of the Mt. Angel Fault in the Willamette Valley, Oregon: Collaborative Research with the Oregon Department of Geology and Mineral Industries and William Lettis & Associates, Inc., funded by the U.S. Geological Survey’s National Earthquake Hazards Reduction Program, Project Period: April 2006 to March 2007..

Pilot Investigation of Potential Cascadia Tsunami Sources Constrained by Geologic, Geophysical and Paleoseismic Data, funded by the National Oceanic and Atmospheric Administration, Project Period: June 2006 to December 2006.


Background Information

1999-2006, Senior Project Geologist, William Lettis & Associates, Inc., Walnut Creek, California
1992-1999, Ph.D., Geological Sciences, University of Oregon, Eugene, Oregon.
1986-1991, B.A., Biology, Whitman College, Walla Walla, Washington.

Professional Societies:
Geological Society of America
Seismological Society of America
American Geophysical Union

Registration:
Professional Geologist, California, P.G. #7565.


Research Interests

       Coastal Earthquake and Tsunami Hazards
       -  Coastal deformation produced by the earthquake cycle
       -  Differentiating tsunami and storm deposits
       -  Probabilistic tsunami hazard assessment
       -  Earthquake source characterization
       -  Paleotsunami runup and inundation
       -  Tsunami erosion features
       -  Coastal paleoseismology

       Coastal Geologic Hazards
       -  Impacts of climate change and sea-level change on coastal hazards
       -  Estimating historic bluff retreat rates on the Oregon coast
       -  Modeling shoreline change through time
       -  Erosion and landslide hazard mapping
       -  Holocene relative sea-level change

       Continental Earthquake Hazards
       -  Geologic controls on the repeatability of lateral spreading
       -  Paleoseismology of Pacific Northwest crustal faults
       -  Liquefaction susceptibility mapping

       Quaternary Geology and Geomorphology
       -  Geomorphic processes controlling forest soil development
       -  Landslides and debris flows in the Oregon Coast Range
       -  Fluvial geomorphology of the Oregon Coast Range
       -  Regional Quaternary geologic mapping.


Publications

Recent Publications:

Witter, R.C., Knudsen, K.L, Sowers, J.M., Wentworth, C.M., Koehler, R.D., Randolph, C.E., Brooks, S.K., Gans, K.D., 2006, Maps of Quaternary deposits and liquefaction susceptibility in the central San Francisco Bay region, California: U.S. Geological Survey Open-File Report 2006-1037 [available on the World Wide Web at URL http://pubs.usgs.gov/of/2006/1037/].

Nelson, A.R., H.M. Kelsey, and R.C. Witter, 2006, Great earthquakes of variable magnitude at the Cascadia subduction zone, Quaternary Research, 65, 354-365.

Kelsey, H.M., Nelson, A.R., Hemphill-Haley, E., and Witter, R.C., 2005, Tsunami history of an Oregon coastal lake reveals a 4,600 yr record of great earthquakes on the Cascadia subduction zone: Geological Society of America Bulletin, v. 117, n.7/8, p. 1009-1032.

Johnson, S.Y., Nelson, A.R., Personius, S.F., Wells, R.E., Kelsey, H.M., Sherrod, B.L., Okumura, K., Koehler, III, R., Witter, R.C., Bradley, L., and Harding, D.J., 2004, Evidence for Late Holocene Earthquakes on the Utsalady Point Fault, Northern Puget Lowland, Washington: Bulletin of the Seismological Society of America, v. 94, n. 6, p. 2299-2316.

Witter, R.C., H.M. Kelsey, and E. Hemphill-Haley, 2003, Great Cascadia earthquakes and tsunamis of the past 6,700 years, Coquille River estuary, southern coastal Oregon, Geological Society of America Bulletin, 115, 10, 1289-1306.

Johnson, S.Y., Nelson, A.R., Personius, S.F., Wells, R.E., Kelsey, H.M., Sherrod, B.L., Okumura, K., Koehler, III., R., Witter, R.C., Bradley, L., and Harding, D.J., 2003, Maps and data from a trench investigation of the Utsalady Point fault, Whidbey Island, Washington, U.S. Geol. Surv. Misc. Invest. Map 2420, 1 plate.

Kelsey, H.M., R.C. Witter, and E. Hemphill-Haley, 2002, Plate-boundary earthquakes and tsunamis of the past 5500 yr, Sixes River estuary, southern Oregon, Geological Society of America Bulletin, 114, 3, 298-314.

Knudsen, K.L., R.C. Witter, C.E. Garrison-Laney, J.N. Baldwin, and G.A. Carver, 2002, Past Earthquake-Induced Rapid Subsidence along the Northern San Andreas Fault: A New Paleoseismological Method for Investigating Strike-Slip Faults, Bulletin of the Seismological Society of America, v. 92, n. 7, p. 2612-2636.

Lettis, W., J. Bachhuber, R. Witter, C. Brankman, C.E. Randolph, A. Barka, W.D. Page, and A. Kaya, 2002, Influence of releasing step-overs on surface fault rupture and fault segmentation: Examples from the 17 August 1999 Izmit earthquake on the north Anatolian fault, Turkey, Bulletin of the Seismological Society of America, 92, 1, 19-42.

Witter, R.C., H.M. Kelsey, and E. Hemphill-Haley, 2001, Pacific storms, El Niño and tsunami: Competing mechanisms for sand deposition in a coastal marsh, Euchre Creek, Oregon, Journal of Coastal Research, 17, 3, 563-583.

Witter, R.C., H.M. Kelsey, and E. Hemphill-Haley, 2000, Stratigraphic evidence for twelve Cascadia earthquakes in the last 6600 years from the Coquille River estuary, Oregon, in J.J. Clague, B.F. Atwater, K. Wang, M.-M. Wang, and I. Wong, eds., Proceedings of the Geological Society of America Penrose Conference: Great Cascadia Earthquake Tricentennial, Oregon Dept. Geology and Mineral Industries, p. 121.

Witter, R.C., W.R. Lettis, J.L. Bachhuber, A. Barka, E.Evren, Z.Cakir, W.D. Page, J.V. Hengesh, and G. Seitz, 2000, Paleoseismic Trenching Study Across the Yalova Segment of the North Anatolian Fault, Hersek Peninsula, Turkey, in A. Barka, O. Kazaci, S. Akyüz, and E. Altunel (eds.), The 1999 Izmit and Düzce Earthquakes: Preliminary Results, Istanbul Technical University, pp. 329-339.

Kelsey, H.M., R.C. Witter, and E. Hemphill-Haley, 1998, Response of a small Oregon estuary to coseismic subsidence and post seismic uplift in the last 300 years, Geology, 26, 231-234.

Unpublished Technical Reports:

Witter, R.C., and R.W. Givler, M. Zeliff, C. Iacoboni, and R.J. Carson, 2006, Two post-glacial earthquakes on the Saddle Mountain West fault, southeastern Olympic Peninsula, Washington: U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report [Grant award number 05HQGR0089], 42 p., 2 plates.

R.D. Koehler, R.C. Witter, G.D. Simpson, E. Hemphill-Haley, and W.R. LEttis, 2005, Paleoseismic investigation of the northern San Gregorio fault, Half Moon Bay, California: U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report [Grant award number 04HQGR0045], alternately paginated.

Baldwin, J.N., R.W. Givler, and R.C. Witter, 2004, Geologic and paleoseismic characterization of the New Madrid North fault, Farrenburg, southeastern Missouri: U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report [Grant award number 02HQGR0024], alternately paginated.

Baldwin, J.N., and Witter, R.C., 2004, Paleoseismic investigation of the Idalia Hill fault along the Commerce geophysical lineament, Idalia, Missouri: U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report [Grant award number 03HQGR0095], 69 p.

Randolph Loar, C.E., Witter, R.C., and Lettis, W.R., 2004, Paleoseismic Investigation of the Southern Rodgers Creek Fault, Martinelli Ranch, Sonoma County, CA: U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 03HQGR0083], 38 p.

Thompson, S.C., Witter, R.C., Givler, R.W., Hitchcock, C.S., and Lettis, W.R., 2004, Evaluating the repeatability of lateral spreading: U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 03HQGR0075], 54 p.

Witter, R.C., K.I. Kelson, and Sundermann, S., 2004a, Paleoseismology of a secondary strand of the central Calaveras fault in Halls Valley, Santa Clara County, CA: U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 03HQGR0098], 32 p.

Witter, R.C. and Kelsey, H.M., 2004b, Middle to Late Holocene earthquake chronologies for the Cascadia subduction zone from two estuaries in southern Oregon: Collaborative research with William Lettis & Associates, Inc. and Humboldt State University U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 02HQGR0057], 40 p.

Koehler, R.D., Simpson, G.D., Witter, R.C., Hemphill-Haley, E., and Lettis, W.R., 2003, Paleoseismic Investigation of the Northern San Gregorio Fault at Pillar Point Marsh near Half Moon Bay, California: U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 02HQPA0001], 64 p.

Witter, R.C., K.I. Kelson, A.D. Barron, and S.T. Sundermann, 2003, Map of active fault traces, geomorphic features and Quaternary surficial deposits along the central Calaveras fault, Santa Clara County, California: U.S. Geological Survey, National Earthquake Hazards Reduction Program Final Technical Report, [Grant award number 01HQGR0212], 32 p.

Witter, R.C., Patton, J.R., Carver, G.A., H.M. Kelsey, C. Garrison-Laney, R.D. Koehler, and E. Hemphill-Haley, 2002, Upper-plate earthquakes on the western Little Salmon fault and contemporaneous subsidence of southern Humboldt Bay over the past 3,600 years, northwestern California, U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report, [Grant award number 01HQGR0125], 44 p.

Witter, R.C., Kelsey, H.M., and Hemphill-Haley, E., 1999, A paleoseismic history of the south-central Cascadia subduction zone: Assessing earthquake recurrence intervals and upper-plate deformation over the past 6600 years at the Coquille River estuary, southern Oregon, U.S.A., U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report [Grant award number 1434-HQ-97-GR-03036], 54 p.

Witter, R.C., K.L. Knudsen, 2000, Geomorphic characterization of prehistoric environments at Crissy Field, San Francisco, California, unpublished final report prepared for Holman & Associates, San Francisco, 21 p.

Knudsen, K.L., J.M. Sowers, R.C. Witter, C.M. Wentworth, and E.J. Helley, 2000, Preliminary Maps of Quaternary Deposits and Liquefaction Susceptibility, Nine-County San Francisco Bay Region, California: A Digital Database, U.S. Geological Survey Open-File Report 00-444. Digital Database by Wentworth, C.M., Nicholson, R.S., Wright, H.M., and Brown, K.H. Online Version 1.0.

Knudsen, K.L., R.C. Witter, C.E. Garrison-Laney, J.N. Baldwin, and G.A. Carver, 1999, Evidence for earthquake-induced, rapid subsidence in estuarine sediment along the northern San Andreas fault, U.S. Geological Survey, National Earthquake Hazard Reduction Program Final Technical Report, 44 p. [Grant award number 1434HQ97GR03009]

Dissertation:

Witter, R.C., 1999, Late Holocene paleoseismicity, tsunamis and relative sea-level changes along the south-central Cascadia subduction zone, southern Oregon, U.S.A.: Ph.D. dissertation, Eugene, University of Oregon, 178 p.