A vibracore taken from a marshy area in Anahola Valley, Kaua‛i reveals a sandier mud layer.
SeanPaul La Selle
Geologist with the USGS Pacific Coastal and Marine Science Center
Science and Products
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
Coastal and marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. These underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis. The tectonically active west coast of the Americas is prone to such hazards, as it lies along the boundaries of major tectonic plates that make up the Earth's crust—the North American, Caribbean...
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Big Sur Landslides, Deep Sea Exploration, Mapping and Characterization, Subduction Zone Science
Tsunami Hazards, Modeling, and the Sedimentary Record
Basic research to develop the geologic record of paleotsunamis and improve the ability to interpret that record is needed to mitigate tsunami risk in the U.S.
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Multi-Sensor Core Logger Laboratory, Sediment Lab Suite and Carbon Analysis Laboratory, Subduction Zone Science
Sediment core data collected from Cargill Marsh, South San Francisco Bay, California during field activities 2022-643-FA and 2023-681-FA
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected cores in the Cargill Marsh section of Whales Tail South Marsh in Eden Landing Ecological Reserve in Alameda County, California in 2022 and 2023. This data release includes photographs, computed tomography (CT) scans, and radiometric data. Details on core locations and measured variables are included in...
Seismic sub-bottom, sediment core and radiocarbon data collected in Ozette Lake, Washington from 2019-2021
Seismic-reflection data and cores were collected in Ozette Lake, Washington, from 2019 to 2021. These data were used to investigate submarine landslide deposits triggered by large Cascadia Subduction Zone earthquakes. Identification of fault-related submarine hazards is a primary mission of the USGS Coastal and Marine Geology Program. In the US Pacific Northwest region, the greatest...
Tsunami deposit data and sediment transport models from the Salmon River estuary, central Oregon
This data release contains sedimentological data and numerical models representing the circa 1700 CE tsunami in the Salmon River estuary, Oregon. The thickness of sandy tsunami deposits was identified in hundreds of cores that map the extent of the deposit throughout the estuary. Grainsize data demonstrate the inland fining of the sandy tsunami deposits. The distribution of tsunami...
Computed Tomography (CT) scans of sediment cores collected from Montague Island, AK
This data release contains Computed Tomography (CT) scan images of sediment cores collected from Montague Island, in Prince William Sound, Alaska. Sediment cores were collected from lagoons uplifted >3 m in the 1964 earthquake along the coast of Montague Island and aid in interpreting changes in deposition environment over the past several thousand years, which may record evidence for...
Sediment core data from offshore southern Cascadia during field activity 2019-643-FA
This data release contains sediment core data including core imagery, multi-sensor core logger (MSCL) data, and radiocarbon age data. Sediment cores were collected offshore northern California during U.S. Geological Survey cruise 2019-643-FA aboard the M/V Bold-Horizon. The cores were collected along with geophysical data to evaluate potential hazards (e.g., active fault systems, slope...
Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone
The USGS Powell Center Cascadia earthquake hazards working group compiled published onshore and offshore paleoseismic data along the Cascadia subduction zone, spanning sites from Vancouver Island to the Mendocino triple junction. Evidence for megathrust rupture includes coastal land-level change, tsunami inundation, onshore shaking proxies such as landslides or liquefaction, and offshore...
Bathymetry and acoustic backscatter data from Floras Lake, Oregon, June 2018
This publication releases single-beam bathymetry and backscatter datasets acquired by the U.S. Geological Survey (USGS) during surveys performed on Floras Lake, Oregon, in June 2018. Bathymetry and backscatter data were collected using two personal watercraft (PWCs) equipped with single-beam sonar systems, sidescan sonar systems, and global navigation satellite system (GNSS) receivers...
Computed Tomography (CT) scans, photographs, X-ray Fluorescence (XRF) scans, grain size, and gamma-ray bulk density data of vibracores from Searsville Lake, Jasper Ridge Biological Preserve, Stanford, California
This data release presents measurements and data from two vibracores (JRBP2018-VC01A and JRBP2018-VC01B collected from Searsville Lake, a reservoir in Jasper Ridge Biological Preserve, Stanford, California, on October 29, 2018 (USGS Field Activity 2018-682-FA).
Observations of tsunami and runup heights in Santa Cruz Harbor and surrounding beaches from the 2022 Hunga Tonga-Hunga Ha'apai tsunami
The 14 January 2022 eruption of Tonga Hunga-Tonga Ha'apai volcano generated tsunamis that impacted the west coast of the United States on the morning of 15 January 2022. This data release presents runup heights and tsunami heights collected by the U.S. Geological Survey (USGS) and the California Geological Survey (CGS) during surveys at the Santa Cruz Harbor and beaches in Santa Cruz...
Vibracore CT scans from the San Lorenzo River
This data release contains information on computed tomography (CT) images of a vibracore that was collected by the U.S. Geological Survey in 2019. A site next to the San Lorenzo River in Henry Cowell Redwoods State Park, California, was cored to understand the history of recent vertical incision and floodplain abandonment. The core was split into 3 segments after collection. Each segment...
Radiocarbon, Cesium-137, Grain Size, and X-ray Fluorescence Data for Tsunami Geology Investigation, Driftwood Bay, Umnak Island, Alaska (2018)
These files provide the complete data release for the paper entitled, "Frequent large tsunamis spanned locked/creeping parts of the Aleutian megathrust." The data set consists of nine tables that include radiocarbon dates, cesium-137 activity, grain size measurements, and scanning X-ray fluorescence element intensity counts.
Core logs, scans, photographs, grain size, and radiocarbon data from coastal wetlands on the Hawaiian islands of Kaua`i, O`ahu, and Hawai`i
Over the past 200 years of written records, the Hawaiian Islands have experienced tens of tsunamis generated by earthquakes in the subduction zones of the Pacific "Ring of Fire" (for example, Alaska-Aleutian, Kuril-Kamchatka, Chile, and Japan). Mapping and dating anomalous beds of sand and silt along the coasts of these subduction zones are critical for assessing the hazard from distant...
A vibracore taken from a marshy area in Anahola Valley, Kaua‛i reveals a sandier mud layer.
Filter Total Items: 15
Testing megathrust rupture models using tsunami deposits
The 26 January 1700 CE Cascadia subduction zone earthquake ruptured much of the plate boundary and generated a tsunami that deposited sand in coastal marshes from northern California to Vancouver Island. Although the depositional record of tsunami inundation is extensive in some of these marshes, few sites have been investigated in enough detail to map the inland extent of sand...
Authors
SeanPaul La Selle, Alan R. Nelson, Robert C. Witter, Bruce E. Jaffe, Guy Gelfenbaum, Jason Scott Padgett
A great tsunami earthquake component of the 1957 Aleutian Islands earthquake
The great 1957 Aleutian Islands earthquake ruptured ∼1200 km of the plate boundary along the Aleutian subduction zone and produced a destructive tsunami across Hawaiʻi. Early seismic and tsunami analyses indicated that large megathrust fault slip was concentrated in the western Aleutian Islands, but tsunami waves generated by slip in the west cannot explain the large observed runup in...
Authors
Yoshiki Yamazaki, Thorne Lay, Kwok Fai Cheung, Robert C. Witter, SeanPaul La Selle, Bruce E. Jaffe
Witnessing history: Comparison of a century of sedimentary and written records in a California protected area
We use a combination of proxy records from a high-resolution analysis of sediments from Searsville Lake and adjacent Upper Lake Marsh and historical records to document over one and a half centuries of vegetation and socio-ecological change—relating to logging, agricultural land use change, dam construction, chemical applications, recreation, and other drivers—on the San Francisco...
Authors
R. Scott Anderson, M. Allison Stegner, SeanPaul La Selle, Brian Sherrod, Anthony D. Barnosky, Elizabeth A. Hadly
The Searsville Lake Site (California, USA) as a candidate Global boundary Stratotype Section and Point for the Anthropocene series
Cores from Searsville Lake within Stanford University’s Jasper Ridge Biological Preserve, California, USA, are examined to identify a potential GSSP for the Anthropocene: core JRBP2018-VC01B (944.5 cm-long) and tightly correlated JRBP2018-VC01A (852.5 cm-long). Spanning from 1900 CE ± 3 years to 2018 CE, a secure chronology resolved to the sub-annual level allows detailed exploration of...
Authors
M. Allison Stegner, Elizabeth A. Hadly, Anthony D. Barnosky, SeanPaul La Selle, Brian Sherrod, R. Scott Anderson, Sergio A. Redondo, Maria Viteri, Karrie Weaver, Andrew Cundy, Pawel Gaca, Neil Rose, Handong Yang, Sarah A. Roberts, Irka Hajdas, Bryan A. Black, Trisha Spanbauer
Diverse tsunamigenesis triggered by the Hunga Tonga-Hunga Ha’apai eruption
On the evening of 15 January 2022, the Hunga Tonga-Hunga Ha’apai volcano1 unleashed a violent underwater eruption, blanketing the surrounding land masses in ash and debris. The eruption generated tsunamis observed around the world. An event of this type last occurred in 1883 during the eruption of Krakatau, and thus we have the first observations of a tsunami from a large emergent...
Authors
Patrick Lynett, Maile McCann, Zili Zhou, Willington Renteria, Jose Borrero, Dougal Greer, 'Ofa Fa'anunu, Cyprien Bosserelle, Bruce E. Jaffe, SeanPaul La Selle, Andrew C. Ritchie, Alexander G. Snyder, Brandon Nasr, Jaqueline Bott, Nicholas A Graehl, Costas Synolakis, Behzad Ebrahimi, Ezgi Cinar
Storm and tsunami overwash sediment transport inferred from recent deposits
Overwash deposits from storms and tsunamis record information about sediment transport and flow that can be used to inform hazard assessments. Here we explore deposits from two extreme wave events: (1) the 2012 Hurricane Sandy, a Category 5 hurricane that is the largest storm in the Atlantic basin on historical record, and (2) the 2011 Tohoku-oki tsunami, created by a 9.0 Mw earthquake...
Authors
Bruce E. Jaffe, SeanPaul La Selle
Can modeling the geologic record contribute to constraining the tectonic source of the AD 1755 Great Lisbon earthquake?
The precise location of the seismic source of 1755 CE Great Lisbon earthquake is still uncertain. The aim of this work is to use an onland sedimentary record in southern Portugal to test and validate seismic sources for the earthquake. To achieve this, tsunami deposit thicknesses from over 150 cores collected at Salgados in southern Portugal were compared to the results of a tsunami...
Authors
Francisco Dourado, Pedro JM Costa, SeanPaul La Selle, Caesar Andrade, Ivana Bosnic, Guy R. Gelfenbaum
River floodplain abandonment and channel deepening coincide with the onset of clear-cut logging in a coastal California redwood forest
Changes in both land use and climate can alter the balance of transport capacity and sediment supply in rivers. Hence, the primary driver of recent incision or aggradation in alluvial channels is often unclear. The San Lorenzo River on the central coast of California is one location where both climate and land use—specifically, clear-cut forestry of coastal redwoods—could explain recent...
Authors
William A. L. Chapman, Noah J. Finnegan, Allison M. Pfeiffer, SeanPaul La Selle
Onshore flow characteristics of the 1755 CE Lisbon tsunami: Linking forward and inverse numerical modeling
The 1755 CE Lisbon earthquake triggered the largest historical tsunami ever impacting the Atlantic coasts of Europe. Despite recent efforts to better understand this event, there are still unanswered questions about the location of its epicenter and whether physical and historical evidences are in agreement.Inverse modeling using tsunami sediments can be applied to quantify onshore flow...
Authors
Ivana Bosnic, Pedro JM Costa, Francisco Dourado, SeanPaul La Selle, Guy R. Gelfenbaum
Selective sediment transport during Hurricane Sandy on Fire Island (New York, USA): Inferences from heavy-mineral assemblages
In October 2012, Hurricane Sandy caused severe erosion on beaches and dunes of Fire Island (New York, USA). Major shoreline changes occurred with erosional dominance in the upper shoreline and aggradation in the lowermost section of the beach due to the deposition of eroded upper beach and dune sediment. Sand laminations with a high concentration of heavy minerals (“black sand...
Authors
João Cascalho, Pedro Costa, Guy R. Gelfenbaum, SeanPaul La Selle, Bruce E. Jaffe
The roles of flow acceleration and deceleration in sediment suspension in the surf zone
Prediction of sediment suspension in the surf zone remains elusive. We explore how suspended sediment concentration at 19 cm above the bed in the mid-surf zone during a storm is influenced by flow acceleration and deceleration. There is a tendency for higher suspended sediment concentrations during onshore flow, with decelerating onshore flows having higher concentrations than steady...
Authors
Bruce E. Jaffe, SeanPaul La Selle
Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust
At the eastern end of the 1957 Andreanof Islands magnitude-8.6 earthquake rupture, Driftwood Bay (Umnak Island) and Stardust Bay (Sedanka Island) lie along presently locked and creeping parts of the Aleutian megathrust, respectively, based on satellite geodesy onshore. Both bays, located 200-km apart, face the Aleutian trench and harbor coastal evidence for tsunami inundation in 1957...
Authors
Robert C. Witter, Richard W. Briggs, Simon E. Engelhart, Guy R. Gelfenbaum, Richard D Koehler, Alan R. Nelson, SeanPaul La Selle, Reide Corbett, Kristi L. Wallace
Science and Products
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
Coastal and marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. These underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis. The tectonically active west coast of the Americas is prone to such hazards, as it lies along the boundaries of major tectonic plates that make up the Earth's crust—the North American, Caribbean...
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Big Sur Landslides, Deep Sea Exploration, Mapping and Characterization, Subduction Zone Science
Tsunami Hazards, Modeling, and the Sedimentary Record
Basic research to develop the geologic record of paleotsunamis and improve the ability to interpret that record is needed to mitigate tsunami risk in the U.S.
By
Natural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Multi-Sensor Core Logger Laboratory, Sediment Lab Suite and Carbon Analysis Laboratory, Subduction Zone Science
Sediment core data collected from Cargill Marsh, South San Francisco Bay, California during field activities 2022-643-FA and 2023-681-FA
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected cores in the Cargill Marsh section of Whales Tail South Marsh in Eden Landing Ecological Reserve in Alameda County, California in 2022 and 2023. This data release includes photographs, computed tomography (CT) scans, and radiometric data. Details on core locations and measured variables are included in...
Seismic sub-bottom, sediment core and radiocarbon data collected in Ozette Lake, Washington from 2019-2021
Seismic-reflection data and cores were collected in Ozette Lake, Washington, from 2019 to 2021. These data were used to investigate submarine landslide deposits triggered by large Cascadia Subduction Zone earthquakes. Identification of fault-related submarine hazards is a primary mission of the USGS Coastal and Marine Geology Program. In the US Pacific Northwest region, the greatest...
Tsunami deposit data and sediment transport models from the Salmon River estuary, central Oregon
This data release contains sedimentological data and numerical models representing the circa 1700 CE tsunami in the Salmon River estuary, Oregon. The thickness of sandy tsunami deposits was identified in hundreds of cores that map the extent of the deposit throughout the estuary. Grainsize data demonstrate the inland fining of the sandy tsunami deposits. The distribution of tsunami...
Computed Tomography (CT) scans of sediment cores collected from Montague Island, AK
This data release contains Computed Tomography (CT) scan images of sediment cores collected from Montague Island, in Prince William Sound, Alaska. Sediment cores were collected from lagoons uplifted >3 m in the 1964 earthquake along the coast of Montague Island and aid in interpreting changes in deposition environment over the past several thousand years, which may record evidence for...
Sediment core data from offshore southern Cascadia during field activity 2019-643-FA
This data release contains sediment core data including core imagery, multi-sensor core logger (MSCL) data, and radiocarbon age data. Sediment cores were collected offshore northern California during U.S. Geological Survey cruise 2019-643-FA aboard the M/V Bold-Horizon. The cores were collected along with geophysical data to evaluate potential hazards (e.g., active fault systems, slope...
Compiled onshore and offshore paleoseismic data along the Cascadia Subduction zone
The USGS Powell Center Cascadia earthquake hazards working group compiled published onshore and offshore paleoseismic data along the Cascadia subduction zone, spanning sites from Vancouver Island to the Mendocino triple junction. Evidence for megathrust rupture includes coastal land-level change, tsunami inundation, onshore shaking proxies such as landslides or liquefaction, and offshore...
Bathymetry and acoustic backscatter data from Floras Lake, Oregon, June 2018
This publication releases single-beam bathymetry and backscatter datasets acquired by the U.S. Geological Survey (USGS) during surveys performed on Floras Lake, Oregon, in June 2018. Bathymetry and backscatter data were collected using two personal watercraft (PWCs) equipped with single-beam sonar systems, sidescan sonar systems, and global navigation satellite system (GNSS) receivers...
Computed Tomography (CT) scans, photographs, X-ray Fluorescence (XRF) scans, grain size, and gamma-ray bulk density data of vibracores from Searsville Lake, Jasper Ridge Biological Preserve, Stanford, California
This data release presents measurements and data from two vibracores (JRBP2018-VC01A and JRBP2018-VC01B collected from Searsville Lake, a reservoir in Jasper Ridge Biological Preserve, Stanford, California, on October 29, 2018 (USGS Field Activity 2018-682-FA).
Observations of tsunami and runup heights in Santa Cruz Harbor and surrounding beaches from the 2022 Hunga Tonga-Hunga Ha'apai tsunami
The 14 January 2022 eruption of Tonga Hunga-Tonga Ha'apai volcano generated tsunamis that impacted the west coast of the United States on the morning of 15 January 2022. This data release presents runup heights and tsunami heights collected by the U.S. Geological Survey (USGS) and the California Geological Survey (CGS) during surveys at the Santa Cruz Harbor and beaches in Santa Cruz...
Vibracore CT scans from the San Lorenzo River
This data release contains information on computed tomography (CT) images of a vibracore that was collected by the U.S. Geological Survey in 2019. A site next to the San Lorenzo River in Henry Cowell Redwoods State Park, California, was cored to understand the history of recent vertical incision and floodplain abandonment. The core was split into 3 segments after collection. Each segment...
Radiocarbon, Cesium-137, Grain Size, and X-ray Fluorescence Data for Tsunami Geology Investigation, Driftwood Bay, Umnak Island, Alaska (2018)
These files provide the complete data release for the paper entitled, "Frequent large tsunamis spanned locked/creeping parts of the Aleutian megathrust." The data set consists of nine tables that include radiocarbon dates, cesium-137 activity, grain size measurements, and scanning X-ray fluorescence element intensity counts.
Core logs, scans, photographs, grain size, and radiocarbon data from coastal wetlands on the Hawaiian islands of Kaua`i, O`ahu, and Hawai`i
Over the past 200 years of written records, the Hawaiian Islands have experienced tens of tsunamis generated by earthquakes in the subduction zones of the Pacific "Ring of Fire" (for example, Alaska-Aleutian, Kuril-Kamchatka, Chile, and Japan). Mapping and dating anomalous beds of sand and silt along the coasts of these subduction zones are critical for assessing the hazard from distant...
Ocean sand in wetland core
A vibracore taken from a marshy area in Anahola Valley, Kaua‛i reveals a sandier mud layer.
A vibracore taken from a marshy area in Anahola Valley, Kaua‛i reveals a sandier mud layer.
Filter Total Items: 15
Testing megathrust rupture models using tsunami deposits
The 26 January 1700 CE Cascadia subduction zone earthquake ruptured much of the plate boundary and generated a tsunami that deposited sand in coastal marshes from northern California to Vancouver Island. Although the depositional record of tsunami inundation is extensive in some of these marshes, few sites have been investigated in enough detail to map the inland extent of sand...
Authors
SeanPaul La Selle, Alan R. Nelson, Robert C. Witter, Bruce E. Jaffe, Guy Gelfenbaum, Jason Scott Padgett
A great tsunami earthquake component of the 1957 Aleutian Islands earthquake
The great 1957 Aleutian Islands earthquake ruptured ∼1200 km of the plate boundary along the Aleutian subduction zone and produced a destructive tsunami across Hawaiʻi. Early seismic and tsunami analyses indicated that large megathrust fault slip was concentrated in the western Aleutian Islands, but tsunami waves generated by slip in the west cannot explain the large observed runup in...
Authors
Yoshiki Yamazaki, Thorne Lay, Kwok Fai Cheung, Robert C. Witter, SeanPaul La Selle, Bruce E. Jaffe
Witnessing history: Comparison of a century of sedimentary and written records in a California protected area
We use a combination of proxy records from a high-resolution analysis of sediments from Searsville Lake and adjacent Upper Lake Marsh and historical records to document over one and a half centuries of vegetation and socio-ecological change—relating to logging, agricultural land use change, dam construction, chemical applications, recreation, and other drivers—on the San Francisco...
Authors
R. Scott Anderson, M. Allison Stegner, SeanPaul La Selle, Brian Sherrod, Anthony D. Barnosky, Elizabeth A. Hadly
The Searsville Lake Site (California, USA) as a candidate Global boundary Stratotype Section and Point for the Anthropocene series
Cores from Searsville Lake within Stanford University’s Jasper Ridge Biological Preserve, California, USA, are examined to identify a potential GSSP for the Anthropocene: core JRBP2018-VC01B (944.5 cm-long) and tightly correlated JRBP2018-VC01A (852.5 cm-long). Spanning from 1900 CE ± 3 years to 2018 CE, a secure chronology resolved to the sub-annual level allows detailed exploration of...
Authors
M. Allison Stegner, Elizabeth A. Hadly, Anthony D. Barnosky, SeanPaul La Selle, Brian Sherrod, R. Scott Anderson, Sergio A. Redondo, Maria Viteri, Karrie Weaver, Andrew Cundy, Pawel Gaca, Neil Rose, Handong Yang, Sarah A. Roberts, Irka Hajdas, Bryan A. Black, Trisha Spanbauer
Diverse tsunamigenesis triggered by the Hunga Tonga-Hunga Ha’apai eruption
On the evening of 15 January 2022, the Hunga Tonga-Hunga Ha’apai volcano1 unleashed a violent underwater eruption, blanketing the surrounding land masses in ash and debris. The eruption generated tsunamis observed around the world. An event of this type last occurred in 1883 during the eruption of Krakatau, and thus we have the first observations of a tsunami from a large emergent...
Authors
Patrick Lynett, Maile McCann, Zili Zhou, Willington Renteria, Jose Borrero, Dougal Greer, 'Ofa Fa'anunu, Cyprien Bosserelle, Bruce E. Jaffe, SeanPaul La Selle, Andrew C. Ritchie, Alexander G. Snyder, Brandon Nasr, Jaqueline Bott, Nicholas A Graehl, Costas Synolakis, Behzad Ebrahimi, Ezgi Cinar
Storm and tsunami overwash sediment transport inferred from recent deposits
Overwash deposits from storms and tsunamis record information about sediment transport and flow that can be used to inform hazard assessments. Here we explore deposits from two extreme wave events: (1) the 2012 Hurricane Sandy, a Category 5 hurricane that is the largest storm in the Atlantic basin on historical record, and (2) the 2011 Tohoku-oki tsunami, created by a 9.0 Mw earthquake...
Authors
Bruce E. Jaffe, SeanPaul La Selle
Can modeling the geologic record contribute to constraining the tectonic source of the AD 1755 Great Lisbon earthquake?
The precise location of the seismic source of 1755 CE Great Lisbon earthquake is still uncertain. The aim of this work is to use an onland sedimentary record in southern Portugal to test and validate seismic sources for the earthquake. To achieve this, tsunami deposit thicknesses from over 150 cores collected at Salgados in southern Portugal were compared to the results of a tsunami...
Authors
Francisco Dourado, Pedro JM Costa, SeanPaul La Selle, Caesar Andrade, Ivana Bosnic, Guy R. Gelfenbaum
River floodplain abandonment and channel deepening coincide with the onset of clear-cut logging in a coastal California redwood forest
Changes in both land use and climate can alter the balance of transport capacity and sediment supply in rivers. Hence, the primary driver of recent incision or aggradation in alluvial channels is often unclear. The San Lorenzo River on the central coast of California is one location where both climate and land use—specifically, clear-cut forestry of coastal redwoods—could explain recent...
Authors
William A. L. Chapman, Noah J. Finnegan, Allison M. Pfeiffer, SeanPaul La Selle
Onshore flow characteristics of the 1755 CE Lisbon tsunami: Linking forward and inverse numerical modeling
The 1755 CE Lisbon earthquake triggered the largest historical tsunami ever impacting the Atlantic coasts of Europe. Despite recent efforts to better understand this event, there are still unanswered questions about the location of its epicenter and whether physical and historical evidences are in agreement.Inverse modeling using tsunami sediments can be applied to quantify onshore flow...
Authors
Ivana Bosnic, Pedro JM Costa, Francisco Dourado, SeanPaul La Selle, Guy R. Gelfenbaum
Selective sediment transport during Hurricane Sandy on Fire Island (New York, USA): Inferences from heavy-mineral assemblages
In October 2012, Hurricane Sandy caused severe erosion on beaches and dunes of Fire Island (New York, USA). Major shoreline changes occurred with erosional dominance in the upper shoreline and aggradation in the lowermost section of the beach due to the deposition of eroded upper beach and dune sediment. Sand laminations with a high concentration of heavy minerals (“black sand...
Authors
João Cascalho, Pedro Costa, Guy R. Gelfenbaum, SeanPaul La Selle, Bruce E. Jaffe
The roles of flow acceleration and deceleration in sediment suspension in the surf zone
Prediction of sediment suspension in the surf zone remains elusive. We explore how suspended sediment concentration at 19 cm above the bed in the mid-surf zone during a storm is influenced by flow acceleration and deceleration. There is a tendency for higher suspended sediment concentrations during onshore flow, with decelerating onshore flows having higher concentrations than steady...
Authors
Bruce E. Jaffe, SeanPaul La Selle
Evidence for frequent, large tsunamis spanning locked and creeping parts of the Aleutian megathrust
At the eastern end of the 1957 Andreanof Islands magnitude-8.6 earthquake rupture, Driftwood Bay (Umnak Island) and Stardust Bay (Sedanka Island) lie along presently locked and creeping parts of the Aleutian megathrust, respectively, based on satellite geodesy onshore. Both bays, located 200-km apart, face the Aleutian trench and harbor coastal evidence for tsunami inundation in 1957...
Authors
Robert C. Witter, Richard W. Briggs, Simon E. Engelhart, Guy R. Gelfenbaum, Richard D Koehler, Alan R. Nelson, SeanPaul La Selle, Reide Corbett, Kristi L. Wallace