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.
Science and Products
Alaska Earthquake and Tsunami Hazards
Alaska has more large earthquakes than the rest of the United States combined. More than three-quarters of the state’s population live in an area that can experience a magnitude 7 earthquake. Our research provides objective science that helps stakeholders prepare for and mitigate the effects of future earthquakes and tsunamis, which bolsters the economic health and well-being of Alaska and the...
Alaska Seismic Hazard Map
The National Seismic Hazard Maps developed by the USGS show the spatial probability of peak earthquake-driven ground motion levels. Since the last revisions to the map for Alaska in 2007, scientists have made significant advances in understanding active faulting, fault slip rates, and fault behavior.
Characterizing the Active Queen Charlotte-Fairweather Fault System
This research aims to better characterize the earthquake potential of the southern Fairweather Fault in order to provide more accurate fault source data for the USGS National Seismic Hazard Map. Our approach interrogates lidar data and satellite imagery, applies paleoseismological methods to examine earthquake history, and leverages partnerships with USGS scientists from Colorado and California...
External Grants - Overview
The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
M7.1 November 30, 2018 Anchorage Earthquake
A magnitude 7.1 earthquake struck north of Anchorage, Alaska, on November 30, 2018, at 8:29 a.m. local time (17:29:28 UTC).
Alaska-Aleutian Subduction Zone Studies
Our research team is exploring seismic and aseismic slip along the Alaska-Aleutian arc and studying the prehistoric record of megathrust earthquakes and tsunamis along the Alaska-Aleutian subduction zone Seismic and Aseismic Slip : Tectonic tremor and associated slow slip events represent a newly discovered part of the earthquake cycle. This research aims to understand the process generating...
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
The Cascadia Subduction Zone, located in the U.S. Pacific Northwest and southwestern British Columbia, has hosted magnitude ≥8.0 megathrust earthquakes in the geologic past, a future earthquake is imminent, and the potential impacts could cripple the region. Subduction zone earthquakes represent some of the most devastating natural hazards on Earth. Despite substantial knowledge gained...
Filter Total Items: 26
Panorama of Iceberg Lake
Research scientists overlooking Iceberg Lake in Wrangell - St Elias National Park & Preserve, Alaska.
The Aleutian Cradle of Tsunamis
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, 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.
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.
Evidence of turbidity currents in Eklutna Lake
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.
Ground crack at Sunset Park, Anchorage, AK
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 Dam after 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.
Eagle River landslides, Eagle River, AK
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
Scientist holding dead tree stump
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.
Investigating a marine terrace along the Fairweather Fault
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.
River terraces elevated along the Fairweather Fault
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.
Geologists' camp on Unga Island, Alaska
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
Investigating a trench across the Fairweather Fault
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.
Walking along the Fairweather Fault scarp
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
Surveying the Fairweather Fault trace
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.
Alaska field crew next to a trench
The field crew studies various areas thoughout the fault.
The field crew studies various areas thoughout the fault.
Sediment core showing tsunami deposits on Sitkalidak Island, Alaska
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 on Sitkalidak Island, Alaska
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Driftwood Bay, Umnak 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.
Geologist on a log 23 m above mean tide level in the Cabin Flat area
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.
Camp near 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.
USGS team looking at a tsunami-rafted log above Stardust Bay, Alaska
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.
Science and Products
Alaska Earthquake and Tsunami Hazards
Alaska has more large earthquakes than the rest of the United States combined. More than three-quarters of the state’s population live in an area that can experience a magnitude 7 earthquake. Our research provides objective science that helps stakeholders prepare for and mitigate the effects of future earthquakes and tsunamis, which bolsters the economic health and well-being of Alaska and the...
Alaska Seismic Hazard Map
The National Seismic Hazard Maps developed by the USGS show the spatial probability of peak earthquake-driven ground motion levels. Since the last revisions to the map for Alaska in 2007, scientists have made significant advances in understanding active faulting, fault slip rates, and fault behavior.
Characterizing the Active Queen Charlotte-Fairweather Fault System
This research aims to better characterize the earthquake potential of the southern Fairweather Fault in order to provide more accurate fault source data for the USGS National Seismic Hazard Map. Our approach interrogates lidar data and satellite imagery, applies paleoseismological methods to examine earthquake history, and leverages partnerships with USGS scientists from Colorado and California...
External Grants - Overview
The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
M7.1 November 30, 2018 Anchorage Earthquake
A magnitude 7.1 earthquake struck north of Anchorage, Alaska, on November 30, 2018, at 8:29 a.m. local time (17:29:28 UTC).
Alaska-Aleutian Subduction Zone Studies
Our research team is exploring seismic and aseismic slip along the Alaska-Aleutian arc and studying the prehistoric record of megathrust earthquakes and tsunamis along the Alaska-Aleutian subduction zone Seismic and Aseismic Slip : Tectonic tremor and associated slow slip events represent a newly discovered part of the earthquake cycle. This research aims to understand the process generating...
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
The Cascadia Subduction Zone, located in the U.S. Pacific Northwest and southwestern British Columbia, has hosted magnitude ≥8.0 megathrust earthquakes in the geologic past, a future earthquake is imminent, and the potential impacts could cripple the region. Subduction zone earthquakes represent some of the most devastating natural hazards on Earth. Despite substantial knowledge gained...
Filter Total Items: 26
Panorama of Iceberg Lake
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
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, 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.
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.
Evidence of turbidity currents in Eklutna Lake
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.
Ground crack at Sunset Park, Anchorage, AK
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 Dam after 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.
Eagle River landslides, Eagle River, AK
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
Scientist holding dead tree stump
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.
Investigating a marine terrace along the Fairweather Fault
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.
River terraces elevated along the Fairweather Fault
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.
Geologists' camp on Unga Island, Alaska
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
USGS geologists' camp overlooking Unga Village on Unga Island, Alaska.
Investigating a trench across the Fairweather Fault
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.
Walking along the Fairweather Fault scarp
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
Surveying the Fairweather Fault trace
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.
Alaska field crew next to a trench
The field crew studies various areas thoughout the fault.
The field crew studies various areas thoughout the fault.
Sediment core showing tsunami deposits on Sitkalidak Island, Alaska
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 on Sitkalidak Island, Alaska
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Soil pit exposing tsunami deposits on Sitkalidak Island, Alaska.
Driftwood Bay, Umnak 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.
Geologist on a log 23 m above mean tide level in the Cabin Flat area
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.
Camp near 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.
USGS team looking at a tsunami-rafted log above Stardust Bay, Alaska
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.
USGS Location