Rob Witter, Ph.D.
I conduct geological detective work that uncovers clues about the location, size, and frequency of ancient earthquakes and tsunamis. If we prepare for these hazards we can prevent future earthquakes and tsunamis from becoming future disasters.
I study prehistoric earthquakes along the Pacific-North American plate boundary. I apply aspects of geomorphology, paleoseismology, geodesy, and sea-level studies to decipher the geologic record of ancient earthquakes. Most of my work focuses on great subduction earthquakes capable of generating tsunamis. What I find out contributes to seismic and tsunami hazards assessments used to strengthen building codes and reduce tsunami risk.
Professional Experience
2011 – Present Research Geologist, U.S. Geological Survey, Alaska Science Center, Anchorage, AK
2006 – 2011 Regional Coastal Geologist, Oregon Department of Geology and Mineral Industries, Newport, OR
1999 – 2006 Senior Project Geologist, William Lettis & Associates, Inc., Walnut Creek, CA
Education and Certifications
Ph.D. 1999 University of Oregon, Eugene, OR Geoscience
B.A. 1991 Whitman College, Walla Walla, WA Biology
Science and Products
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New insights of tsunami hazard from the 2011 Tohoku-oki event New insights of tsunami hazard from the 2011 Tohoku-oki event
We report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 Tohoku-oki tsunami from Sendai Plain, Japan. The tsunami inundated up to 4.5 km inland but the > 0.5 cm-thick sand deposit extended only 2.8 km (62% of the inundation distance). The deposit however continued as a mud layer to the inundation limit. The mud deposit contained...
Authors
K. Goto, C. Chague-Goff, S. Fujino, J. Goff, Bruce Jaffe, Y. Nishimura, Bruce M. Richmond, D. Sugawara, Witold Szczucinski, D.R. Tappin, Robert C. Witter, E. Yulianto
Maps of quaternary deposits and liquefaction susceptibility in the Central San Francisco Bay Region, California Maps of quaternary deposits and liquefaction susceptibility in the Central San Francisco Bay Region, California
This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale...
Authors
Robert C. Witter, Keith L. Knudsen, Janet M. Sowers, Carl M. Wentworth, Richard D. Koehler, Carolyn E. Randolph, Suzanna K. Brooks, Kathleen D. Gans
By
Great earthquakes of variable magnitude at the Cascadia subduction zone Great earthquakes of variable magnitude at the Cascadia subduction zone
Comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate-boundary ruptures of varying length, implying great earthquakes of variable magnitude at the Cascadia subduction zone. Inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis, and relative amounts of coseismic subsidence and...
Authors
A.R. Nelson, H.M. Kelsey, Robert C. Witter
Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone
Bradley Lake, on the southern Oregon coastal plain, records local tsunamis and seismic shaking on the Cascadia subduction zone over the last 7000 yr. Thirteen marine incursions delivered landward-thinning sheets of sand to the lake from nearshore, beach, and dune environments to the west. Following each incursion, a slug of marine water near the bottom of the freshwater lake instigated a...
Authors
H.M. Kelsey, A.R. Nelson, E. Hemphill-Haley, Robert C. Witter
Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington
Trenches across the Utsalady Point fault in the northern Puget Lowland of Washington reveal evidence of at least one and probably two late Holocene earthquakes. The "Teeka" and "Duffers" trenches were located along a 1.4-km-long, 1-to 4-m-high, northwest-trending, southwest-facing, topographic scarp recognized from Airborne Laser Swath Mapping. Glaciomarine drift exposed in the trenches...
Authors
S. Johnson, A.R. Nelson, S. F. Personius, R.E. Wells, H.M. Kelsey, B.L. Sherrod, K. Okumura, R. Koehler, Robert C. Witter, L. Bradley, D.J. Harding
Preliminary maps of Quaternary deposits and liquefaction susceptibility, nine-county San Francisco Bay region, California: a digital database Preliminary maps of Quaternary deposits and liquefaction susceptibility, nine-county San Francisco Bay region, California: a digital database
This report presents a preliminary map and database of Quaternary deposits and liquefaction susceptibility for the nine-county San Francisco Bay region, together with a digital compendium of ground effects associated with past earthquakes in the region. The report consists of (1) a spatial database of fivedata layers (Quaternary deposits, quadrangle index, and three ground effects layers...
Authors
Keith L. Knudsen, Janet M. Sowers, Robert C. Witter, Carl M. Wentworth, Edward J. Helley, Robert S. Nicholson, Heather M. Wright, Katherine H. Brown
Non-USGS Publications**
Engelhart, S. E., Horton, B. P., Nelson, A. R., Hawkes, A. D., Witter, R. C., Wang, K., Wang P.-L., and Vane, C. H., 2013, Testing the use of microfossils to reconstruct great earthquakes at Cascadia, Geology, doi:10.1130/G34544.1.
Engelhart, S. E., B. P. Horton, C. H. Vane, A. R. Nelson, R. C. Witter, S. R. Brody, and A. D. Hawkes, 2013, Modern foraminifera, δ13C, and bulk geochemistry of central Oregon tidal marshes and their application in paleoseismology, Palaeogeography, Palaeoclimatology, Palaeoecology, doi:10.1016/j.palaeo.2013.02.032.
Kelson, K., R. C. Witter, A. Tassara, I. Ryder, C. Ledezma, G. Montalva, D. Frost, N. Sitar, R. Moss, and L. Johnson, 2012, Coseismic tectonic surface deformation during the 2012 Maule, Chile, Mw 8.8 earthquake, Earthquake Spectra, v. 28, n. S1, p. 39-54.
Pilarczyk, J. E., Horton, B. P., Witter, R. C., Vane, C. H., Chagué-Goff, C., Goff, J., 2012, Sedimentary and foraminiferal evidence of the 2011 Tohoku-oki tsunami on the Sendai coastal plain, Japan. Sedimentary Geology. doi:10.1016/j.sedgeo.2012.08.011.
Richmond, B., W. Szczucinski, C.Chague-Goff, K. Goto, D. Sugawara, R. Witter, D.R. Tappin, B. Jaffe, S. Fujino, Y. Nishimura, and J. Goff, 2012, Erosion, deposition and landscape change on the Sendai coastal plain, Japan, resulting from the March 11, 2011 Tohoku-oki tsunami, Sedimentary Geology, doi:10.1016/j.sedgeo.2012.08.005.
Witter, R.C., Y.J. Zhang, K. Wang, C. Goldfinger, and G.R. Priest, 2012, Coseismic slip on the southern Cascadia megathrust implied by tsunami deposits in an Oregon lake and earthquake-triggered marine turbidites, Journal of Geophysical Research, 117, B10303, doi:10.1029/2012JB009404.
Allan, J., P. Komar, P. Ruggiero, and R.C. Witter, 2012, The March 2011 Tohoku tsunami and its impacts along the U.S. West Coast, Journal of Coastal Research, Journal of Coastal Research, v. 28, n. 5, p. 1142-1153, doi:10.2112/jcoastres-d-11-00115.1.
Witter, R. C., B. Jaffe, Y. Zhang, and G. R. Priest, 2012, Reconstructing Hydrodynamic Flow Parameters of the 1700 Tsunami at Cannon Beach, Oregon, USA, Natural Hazards, doi:10.1007/s11069-011-9912-7.
Horton, B. P., Sawai, Y., Hawkes, A. D., and Witter, R. C., 2011, Sedimentology and paleontology of a tsunami deposit accompanying the great Chilean earthquake of February 2010: Marine Micropaleontology, v. 79, no. 3-4, p. 132–138, doi:10.1016/j.marmicro.2011.02.001
Zhang, Y. J., R. C. Witter, and G. R. Priest, 2011, Tsunami-tide interaction in 1964 Prince William Sound tsunami, Ocean Modelling, v. 40, p. 246–259, doi:10.1016/j.ocemod.2011.09.005
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 18
No Result Found
Filter Total Items: 26
No results found.
Filter Total Items: 55
New insights of tsunami hazard from the 2011 Tohoku-oki event New insights of tsunami hazard from the 2011 Tohoku-oki event
We report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 Tohoku-oki tsunami from Sendai Plain, Japan. The tsunami inundated up to 4.5 km inland but the > 0.5 cm-thick sand deposit extended only 2.8 km (62% of the inundation distance). The deposit however continued as a mud layer to the inundation limit. The mud deposit contained...
Authors
K. Goto, C. Chague-Goff, S. Fujino, J. Goff, Bruce Jaffe, Y. Nishimura, Bruce M. Richmond, D. Sugawara, Witold Szczucinski, D.R. Tappin, Robert C. Witter, E. Yulianto
Maps of quaternary deposits and liquefaction susceptibility in the Central San Francisco Bay Region, California Maps of quaternary deposits and liquefaction susceptibility in the Central San Francisco Bay Region, California
This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale...
Authors
Robert C. Witter, Keith L. Knudsen, Janet M. Sowers, Carl M. Wentworth, Richard D. Koehler, Carolyn E. Randolph, Suzanna K. Brooks, Kathleen D. Gans
By
Great earthquakes of variable magnitude at the Cascadia subduction zone Great earthquakes of variable magnitude at the Cascadia subduction zone
Comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate-boundary ruptures of varying length, implying great earthquakes of variable magnitude at the Cascadia subduction zone. Inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis, and relative amounts of coseismic subsidence and...
Authors
A.R. Nelson, H.M. Kelsey, Robert C. Witter
Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone Tsunami history of an Oregon coastal lake reveals a 4600 yr record of great earthquakes on the Cascadia subduction zone
Bradley Lake, on the southern Oregon coastal plain, records local tsunamis and seismic shaking on the Cascadia subduction zone over the last 7000 yr. Thirteen marine incursions delivered landward-thinning sheets of sand to the lake from nearshore, beach, and dune environments to the west. Following each incursion, a slug of marine water near the bottom of the freshwater lake instigated a...
Authors
H.M. Kelsey, A.R. Nelson, E. Hemphill-Haley, Robert C. Witter
Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington
Trenches across the Utsalady Point fault in the northern Puget Lowland of Washington reveal evidence of at least one and probably two late Holocene earthquakes. The "Teeka" and "Duffers" trenches were located along a 1.4-km-long, 1-to 4-m-high, northwest-trending, southwest-facing, topographic scarp recognized from Airborne Laser Swath Mapping. Glaciomarine drift exposed in the trenches...
Authors
S. Johnson, A.R. Nelson, S. F. Personius, R.E. Wells, H.M. Kelsey, B.L. Sherrod, K. Okumura, R. Koehler, Robert C. Witter, L. Bradley, D.J. Harding
Preliminary maps of Quaternary deposits and liquefaction susceptibility, nine-county San Francisco Bay region, California: a digital database Preliminary maps of Quaternary deposits and liquefaction susceptibility, nine-county San Francisco Bay region, California: a digital database
This report presents a preliminary map and database of Quaternary deposits and liquefaction susceptibility for the nine-county San Francisco Bay region, together with a digital compendium of ground effects associated with past earthquakes in the region. The report consists of (1) a spatial database of fivedata layers (Quaternary deposits, quadrangle index, and three ground effects layers...
Authors
Keith L. Knudsen, Janet M. Sowers, Robert C. Witter, Carl M. Wentworth, Edward J. Helley, Robert S. Nicholson, Heather M. Wright, Katherine H. Brown
Non-USGS Publications**
Engelhart, S. E., Horton, B. P., Nelson, A. R., Hawkes, A. D., Witter, R. C., Wang, K., Wang P.-L., and Vane, C. H., 2013, Testing the use of microfossils to reconstruct great earthquakes at Cascadia, Geology, doi:10.1130/G34544.1.
Engelhart, S. E., B. P. Horton, C. H. Vane, A. R. Nelson, R. C. Witter, S. R. Brody, and A. D. Hawkes, 2013, Modern foraminifera, δ13C, and bulk geochemistry of central Oregon tidal marshes and their application in paleoseismology, Palaeogeography, Palaeoclimatology, Palaeoecology, doi:10.1016/j.palaeo.2013.02.032.
Kelson, K., R. C. Witter, A. Tassara, I. Ryder, C. Ledezma, G. Montalva, D. Frost, N. Sitar, R. Moss, and L. Johnson, 2012, Coseismic tectonic surface deformation during the 2012 Maule, Chile, Mw 8.8 earthquake, Earthquake Spectra, v. 28, n. S1, p. 39-54.
Pilarczyk, J. E., Horton, B. P., Witter, R. C., Vane, C. H., Chagué-Goff, C., Goff, J., 2012, Sedimentary and foraminiferal evidence of the 2011 Tohoku-oki tsunami on the Sendai coastal plain, Japan. Sedimentary Geology. doi:10.1016/j.sedgeo.2012.08.011.
Richmond, B., W. Szczucinski, C.Chague-Goff, K. Goto, D. Sugawara, R. Witter, D.R. Tappin, B. Jaffe, S. Fujino, Y. Nishimura, and J. Goff, 2012, Erosion, deposition and landscape change on the Sendai coastal plain, Japan, resulting from the March 11, 2011 Tohoku-oki tsunami, Sedimentary Geology, doi:10.1016/j.sedgeo.2012.08.005.
Witter, R.C., Y.J. Zhang, K. Wang, C. Goldfinger, and G.R. Priest, 2012, Coseismic slip on the southern Cascadia megathrust implied by tsunami deposits in an Oregon lake and earthquake-triggered marine turbidites, Journal of Geophysical Research, 117, B10303, doi:10.1029/2012JB009404.
Allan, J., P. Komar, P. Ruggiero, and R.C. Witter, 2012, The March 2011 Tohoku tsunami and its impacts along the U.S. West Coast, Journal of Coastal Research, Journal of Coastal Research, v. 28, n. 5, p. 1142-1153, doi:10.2112/jcoastres-d-11-00115.1.
Witter, R. C., B. Jaffe, Y. Zhang, and G. R. Priest, 2012, Reconstructing Hydrodynamic Flow Parameters of the 1700 Tsunami at Cannon Beach, Oregon, USA, Natural Hazards, doi:10.1007/s11069-011-9912-7.
Horton, B. P., Sawai, Y., Hawkes, A. D., and Witter, R. C., 2011, Sedimentology and paleontology of a tsunami deposit accompanying the great Chilean earthquake of February 2010: Marine Micropaleontology, v. 79, no. 3-4, p. 132–138, doi:10.1016/j.marmicro.2011.02.001
Zhang, Y. J., R. C. Witter, and G. R. Priest, 2011, Tsunami-tide interaction in 1964 Prince William Sound tsunami, Ocean Modelling, v. 40, p. 246–259, doi:10.1016/j.ocemod.2011.09.005
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.