Research scientists overlooking Iceberg Lake in Wrangell - St Elias National Park & Preserve, Alaska.
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
Alaska Earthquake and Tsunami Hazards
Alaska Seismic Hazard Map
Characterizing the Active Queen Charlotte-Fairweather Fault System
External Grants - Overview
M7.1 November 30, 2018 Anchorage Earthquake
Alaska-Aleutian Subduction Zone Studies
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
Tsunami deposit data and sediment transport models from the Salmon River estuary, central Oregon
Computed Tomography (CT) scans of sediment cores collected from Montague Island, AK
Diatom Data from Coastal Environments on Montague Island, Alaska
Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone
Radiocarbon Data from Coastal Environments on Montague Island, Alaska
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
Radiocarbon Data for Tree Ring Samples from Girdwood, Alaska
Quaternary deposits of the 9-county San Francisco Bay Region: an areally continuous digital map database prepared from Knudsen and others (2000) and Witter and others (2006)
Geophysical and core sample data collected in lakes and fjords of southcentral Alaska following the 2018 Anchorage earthquake (ver. 2.0, October 2023)
Radiocarbon and Luminescence Data for Fairweather Fault Investigation, Glacier Bay National Park, Southeast Alaska
Gridded Data from Multibeam Bathymetric Surveys of Eklutna, Kenai, and Skilak Lakes, Alaska
Field reconnaissance of ground failure triggered by shaking during the 2018 M7.1 Anchorage, Alaska, earthquake
Field and Laboratory Data From an Earthquake History Study of Scarps in the Hanging Wall of the Tacoma Fault, Mason and Pierce Counties, Washington
Research scientists overlooking Iceberg Lake in Wrangell - St Elias National Park & Preserve, Alaska.
THE ALEUTIAN CRADLE OF TSUNAMIS
(Click here to read EOS Feature: Seismic Sources in the Aleutian Cradle of Tsunamis)
Geologists climb a slope above Larsen Bay, Nagai Island, Alaska. Geologists studying coastal evidence of past Alaska-Aleutian subduction zone earthquakes and high tsunamis climb a slope above Larsen Bay on Nagai Island in the Shumagin seismic gap, Alaska.
Geologists climb a slope above Larsen Bay, Nagai Island, Alaska. Geologists studying coastal evidence of past Alaska-Aleutian subduction zone earthquakes and high tsunamis climb a slope above Larsen Bay on Nagai Island in the Shumagin seismic gap, Alaska.
USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake.
USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake.
Crack observed in 2018 along headscarp of 1964 Government Hill landslide.
2018 Anchorage Earthquake
Crack observed in 2018 along headscarp of 1964 Government Hill landslide.
2018 Anchorage Earthquake
Eklutna Lake dam appeared to be undamaged the day after the earthquake; overflights of the lake showed no landslides impacted the lake shoreline.
Eklutna Lake dam appeared to be undamaged the day after the earthquake; overflights of the lake showed no landslides impacted the lake shoreline.
Superficial slides along Eagle River east of Eagle River Loop Road.
2018 Anchorage Earthquake
Superficial slides along Eagle River east of Eagle River Loop Road.
2018 Anchorage Earthquake
Research Geologist Peter Haeussler holding a stump from a tree that was killed in the penultimate great earthquake - the last giant earthquake before the 1964 M9.2 earthquake in southcentral Alaska.
Research Geologist Peter Haeussler holding a stump from a tree that was killed in the penultimate great earthquake - the last giant earthquake before the 1964 M9.2 earthquake in southcentral Alaska.
![Three people looking in a hole they dug](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/marine_terrace_along_Fairweather_Fault_6-5-2017_Rob_Witter_0.jpg?itok=2pwlE-77)
USGS scientists Kate Scharer, Richard Lease, and Adrian Bender excavate a marine terrace elevated tens of meters above sea level on the west side of the Fairweather Fault. Location: Icy Point, Glacier Bay National Park, Alaska.
USGS scientists Kate Scharer, Richard Lease, and Adrian Bender excavate a marine terrace elevated tens of meters above sea level on the west side of the Fairweather Fault. Location: Icy Point, Glacier Bay National Park, Alaska.
![Two people on a gravel surface next to a cliff](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/river_terraces_elevated_along_Fairweather_Fault_6-1-2017_Rob_Witter_0.jpg?itok=AXE8O5VZ)
USGS scientists Richard Lease and Adrian Bender examine river terraces elevated tens of meters above the modern channel level on the west side of the Fairweather Fault. Location: Kaknau Creek, Icy Point, Glacier Bay National Park, Alaska.
USGS scientists Richard Lease and Adrian Bender examine river terraces elevated tens of meters above the modern channel level on the west side of the Fairweather Fault. Location: Kaknau Creek, Icy Point, Glacier Bay National Park, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS Research Geologist Chris DuRoss investigates earthquake-faulted stratigraphy exposed in a hand-dug trench across the Fairweather Fault scarp. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS Research Geologist Chris DuRoss investigates earthquake-faulted stratigraphy exposed in a hand-dug trench across the Fairweather Fault scarp. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS scientists Adrian Bender and Peter Haeussler walk along the base of a ~10 m tall escarpment formed during past ground-rupturing earthquakes on the Fairweather Fault. Location: Crillon Lake, Glacier Bay National Park, Alaska
USGS scientists Adrian Bender and Peter Haeussler walk along the base of a ~10 m tall escarpment formed during past ground-rupturing earthquakes on the Fairweather Fault. Location: Crillon Lake, Glacier Bay National Park, Alaska
USGS Geologist Adrian Bender surveys a trace of the 1958 Fairweather Fault earthquake surface rupture. The trace forms a linear, uphill-facing, 1-2 m tall escarpment flanked by trees that were likely tilted during the 1958 earthquake. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS Geologist Adrian Bender surveys a trace of the 1958 Fairweather Fault earthquake surface rupture. The trace forms a linear, uphill-facing, 1-2 m tall escarpment flanked by trees that were likely tilted during the 1958 earthquake. Location: Crillon Lake, Glacier Bay National Park, Alaska.
The field crew studies various areas thoughout the fault.
The field crew studies various areas thoughout the fault.
![Dirt in a long cylinder](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/sediment_core_tsunami_deposits_Sitkalidak_Is_8-7-2015_Rob_Witter.jpg?itok=HAoL9Tnv)
Sediment core showing sandy tsunami deposits over soil from an upland environment on Sitkalidak Island, Alaska.
Sediment core showing sandy tsunami deposits over soil from an upland environment on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
In the Fox Islands of Alaska, Driftwood Bay on Umnak Island faces the deep-sea trench formed by the Alaska-Aleutian subduction zone.
In the Fox Islands of Alaska, Driftwood Bay on Umnak Island faces the deep-sea trench formed by the Alaska-Aleutian subduction zone.
A geologist stands on a drift log stranded 23 m above mean tide level, overlooking the Cabin Flat study site and Driftwood Bay, Umnak Island, Alaska.
A geologist stands on a drift log stranded 23 m above mean tide level, overlooking the Cabin Flat study site and Driftwood Bay, Umnak Island, Alaska.
Geologists camped near an upland lake about 0.5 km from the shore of Driftwood Bay, Umnak Island, Alaska. Vsevidof Volcano in the background.
Geologists camped near an upland lake about 0.5 km from the shore of Driftwood Bay, Umnak Island, Alaska. Vsevidof Volcano in the background.
![Many people looking at a log on a hill](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/tsunami-rafted_drift_log_above_sea_level_Sedanka_Is_8-8-2012_Rob_Witter.jpg?itok=2QmuBJXO)
USGS Alaska Earthquake Hazards research team investigates a tsunami-rafted drift log high above sea level at Stardust Bay, Sedanka Island, Alaska.
USGS Alaska Earthquake Hazards research team investigates a tsunami-rafted drift log high above sea level at Stardust Bay, Sedanka Island, Alaska.
Testing megathrust rupture models using tsunami deposits
A great tsunami earthquake component of the 1957 Aleutian Islands earthquake
The 2023 US 50-State National Seismic Hazard Model: Overview and implications
Seismic sources in the aleutian cradle of tsunamis
Reproducibility and variability of earthquake subsidence estimates from saltmarshes of a Cascadia estuary
Unravelling a 2300 year long sedimentary record of megathrust and intraslab earthquakes in proglacial Skilak Lake, south-central Alaska
Changing impacts of Alaska-Aleutian subduction zone tsunamis in California under future sea-level rise
Geomorphic expression and slip rate of the Fairweather fault, southeast Alaska, and evidence for predecessors of the 1958 rupture
A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis
Extreme Quaternary plate boundary exhumation and strike slip localized along the southern Fairweather fault, Alaska, USA
Timing and amount of southern Cascadia earthquake subsidence over the past 1700 years at northern Humboldt Bay, California, USA
Toward an integrative geological and geophysical view of Cascadia subduction zone earthquakes
Non-USGS Publications**
**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.
WiggleMatch: a spreadsheet for radiocarbon wiggle-matching
Science and Products
Alaska Earthquake and Tsunami Hazards
Alaska Seismic Hazard Map
Characterizing the Active Queen Charlotte-Fairweather Fault System
External Grants - Overview
M7.1 November 30, 2018 Anchorage Earthquake
Alaska-Aleutian Subduction Zone Studies
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
Tsunami deposit data and sediment transport models from the Salmon River estuary, central Oregon
Computed Tomography (CT) scans of sediment cores collected from Montague Island, AK
Diatom Data from Coastal Environments on Montague Island, Alaska
Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone
Radiocarbon Data from Coastal Environments on Montague Island, Alaska
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
Radiocarbon Data for Tree Ring Samples from Girdwood, Alaska
Quaternary deposits of the 9-county San Francisco Bay Region: an areally continuous digital map database prepared from Knudsen and others (2000) and Witter and others (2006)
Geophysical and core sample data collected in lakes and fjords of southcentral Alaska following the 2018 Anchorage earthquake (ver. 2.0, October 2023)
Radiocarbon and Luminescence Data for Fairweather Fault Investigation, Glacier Bay National Park, Southeast Alaska
Gridded Data from Multibeam Bathymetric Surveys of Eklutna, Kenai, and Skilak Lakes, Alaska
Field reconnaissance of ground failure triggered by shaking during the 2018 M7.1 Anchorage, Alaska, earthquake
Field and Laboratory Data From an Earthquake History Study of Scarps in the Hanging Wall of the Tacoma Fault, Mason and Pierce Counties, Washington
Research scientists overlooking Iceberg Lake in Wrangell - St Elias National Park & Preserve, Alaska.
Research scientists overlooking Iceberg Lake in Wrangell - St Elias National Park & Preserve, Alaska.
THE ALEUTIAN CRADLE OF TSUNAMIS
(Click here to read EOS Feature: Seismic Sources in the Aleutian Cradle of Tsunamis)
Geologists climb a slope above Larsen Bay, Nagai Island, Alaska. Geologists studying coastal evidence of past Alaska-Aleutian subduction zone earthquakes and high tsunamis climb a slope above Larsen Bay on Nagai Island in the Shumagin seismic gap, Alaska.
Geologists climb a slope above Larsen Bay, Nagai Island, Alaska. Geologists studying coastal evidence of past Alaska-Aleutian subduction zone earthquakes and high tsunamis climb a slope above Larsen Bay on Nagai Island in the Shumagin seismic gap, Alaska.
USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake.
USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake.
Crack observed in 2018 along headscarp of 1964 Government Hill landslide.
2018 Anchorage Earthquake
Crack observed in 2018 along headscarp of 1964 Government Hill landslide.
2018 Anchorage Earthquake
Eklutna Lake dam appeared to be undamaged the day after the earthquake; overflights of the lake showed no landslides impacted the lake shoreline.
Eklutna Lake dam appeared to be undamaged the day after the earthquake; overflights of the lake showed no landslides impacted the lake shoreline.
Superficial slides along Eagle River east of Eagle River Loop Road.
2018 Anchorage Earthquake
Superficial slides along Eagle River east of Eagle River Loop Road.
2018 Anchorage Earthquake
Research Geologist Peter Haeussler holding a stump from a tree that was killed in the penultimate great earthquake - the last giant earthquake before the 1964 M9.2 earthquake in southcentral Alaska.
Research Geologist Peter Haeussler holding a stump from a tree that was killed in the penultimate great earthquake - the last giant earthquake before the 1964 M9.2 earthquake in southcentral Alaska.
![Three people looking in a hole they dug](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/marine_terrace_along_Fairweather_Fault_6-5-2017_Rob_Witter_0.jpg?itok=2pwlE-77)
USGS scientists Kate Scharer, Richard Lease, and Adrian Bender excavate a marine terrace elevated tens of meters above sea level on the west side of the Fairweather Fault. Location: Icy Point, Glacier Bay National Park, Alaska.
USGS scientists Kate Scharer, Richard Lease, and Adrian Bender excavate a marine terrace elevated tens of meters above sea level on the west side of the Fairweather Fault. Location: Icy Point, Glacier Bay National Park, Alaska.
![Two people on a gravel surface next to a cliff](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/river_terraces_elevated_along_Fairweather_Fault_6-1-2017_Rob_Witter_0.jpg?itok=AXE8O5VZ)
USGS scientists Richard Lease and Adrian Bender examine river terraces elevated tens of meters above the modern channel level on the west side of the Fairweather Fault. Location: Kaknau Creek, Icy Point, Glacier Bay National Park, Alaska.
USGS scientists Richard Lease and Adrian Bender examine river terraces elevated tens of meters above the modern channel level on the west side of the Fairweather Fault. Location: Kaknau Creek, Icy Point, Glacier Bay National Park, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS Research Geologist Chris DuRoss investigates earthquake-faulted stratigraphy exposed in a hand-dug trench across the Fairweather Fault scarp. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS Research Geologist Chris DuRoss investigates earthquake-faulted stratigraphy exposed in a hand-dug trench across the Fairweather Fault scarp. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS scientists Adrian Bender and Peter Haeussler walk along the base of a ~10 m tall escarpment formed during past ground-rupturing earthquakes on the Fairweather Fault. Location: Crillon Lake, Glacier Bay National Park, Alaska
USGS scientists Adrian Bender and Peter Haeussler walk along the base of a ~10 m tall escarpment formed during past ground-rupturing earthquakes on the Fairweather Fault. Location: Crillon Lake, Glacier Bay National Park, Alaska
USGS Geologist Adrian Bender surveys a trace of the 1958 Fairweather Fault earthquake surface rupture. The trace forms a linear, uphill-facing, 1-2 m tall escarpment flanked by trees that were likely tilted during the 1958 earthquake. Location: Crillon Lake, Glacier Bay National Park, Alaska.
USGS Geologist Adrian Bender surveys a trace of the 1958 Fairweather Fault earthquake surface rupture. The trace forms a linear, uphill-facing, 1-2 m tall escarpment flanked by trees that were likely tilted during the 1958 earthquake. Location: Crillon Lake, Glacier Bay National Park, Alaska.
The field crew studies various areas thoughout the fault.
The field crew studies various areas thoughout the fault.
![Dirt in a long cylinder](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/sediment_core_tsunami_deposits_Sitkalidak_Is_8-7-2015_Rob_Witter.jpg?itok=HAoL9Tnv)
Sediment core showing sandy tsunami deposits over soil from an upland environment on Sitkalidak Island, Alaska.
Sediment core showing sandy tsunami deposits over soil from an upland environment on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
In the Fox Islands of Alaska, Driftwood Bay on Umnak Island faces the deep-sea trench formed by the Alaska-Aleutian subduction zone.
In the Fox Islands of Alaska, Driftwood Bay on Umnak Island faces the deep-sea trench formed by the Alaska-Aleutian subduction zone.
A geologist stands on a drift log stranded 23 m above mean tide level, overlooking the Cabin Flat study site and Driftwood Bay, Umnak Island, Alaska.
A geologist stands on a drift log stranded 23 m above mean tide level, overlooking the Cabin Flat study site and Driftwood Bay, Umnak Island, Alaska.
Geologists camped near an upland lake about 0.5 km from the shore of Driftwood Bay, Umnak Island, Alaska. Vsevidof Volcano in the background.
Geologists camped near an upland lake about 0.5 km from the shore of Driftwood Bay, Umnak Island, Alaska. Vsevidof Volcano in the background.
![Many people looking at a log on a hill](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/tsunami-rafted_drift_log_above_sea_level_Sedanka_Is_8-8-2012_Rob_Witter.jpg?itok=2QmuBJXO)
USGS Alaska Earthquake Hazards research team investigates a tsunami-rafted drift log high above sea level at Stardust Bay, Sedanka Island, Alaska.
USGS Alaska Earthquake Hazards research team investigates a tsunami-rafted drift log high above sea level at Stardust Bay, Sedanka Island, Alaska.
Testing megathrust rupture models using tsunami deposits
A great tsunami earthquake component of the 1957 Aleutian Islands earthquake
The 2023 US 50-State National Seismic Hazard Model: Overview and implications
Seismic sources in the aleutian cradle of tsunamis
Reproducibility and variability of earthquake subsidence estimates from saltmarshes of a Cascadia estuary
Unravelling a 2300 year long sedimentary record of megathrust and intraslab earthquakes in proglacial Skilak Lake, south-central Alaska
Changing impacts of Alaska-Aleutian subduction zone tsunamis in California under future sea-level rise
Geomorphic expression and slip rate of the Fairweather fault, southeast Alaska, and evidence for predecessors of the 1958 rupture
A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis
Extreme Quaternary plate boundary exhumation and strike slip localized along the southern Fairweather fault, Alaska, USA
Timing and amount of southern Cascadia earthquake subsidence over the past 1700 years at northern Humboldt Bay, California, USA
Toward an integrative geological and geophysical view of Cascadia subduction zone earthquakes
Non-USGS Publications**
**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.