Research Oceanographer with the USGS Pacific Coastal and Marine Science Center
Science and Products
Sediment Transport in Coastal Environments
Tsunami Hazards, Modeling, and the Sedimentary Record
San Francisco Bay Bathymetry
San Francisco Bay geomorphology
Tsunami Field Studies
Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1
USGS Scientists in Samoa and American Samoa Studying Impacts of Tsunami in 2009
Preliminary Analysis of Sedimentary Deposits from the June 23, 2001 Peru Tsunami
Preliminary Analysis of Sedimentary Deposits from the July 17, 1998 Papua New Guinea Tsunami
Bathymetric surveys collected near Dumbarton Bridge in south San Francisco Bay, California, 2008 to 2019
Observations of tsunami and runup heights in Santa Cruz Harbor and surrounding beaches from the 2022 Hunga Tonga-Hunga Ha'apai tsunami
High-resolution (1 m) digital elevation model (DEM) of San Francisco Bay, California, created using bathymetry data collected between 1999 and 2020 (ver. 2.0, July 2021)
Pilot study on bathymetric change analyses in the Sacramento-San Joaquin Delta, California
Core logs, scans, photographs, grain size, and radiocarbon data from coastal wetlands on the Hawaiian islands of Kaua`i, O`ahu, and Hawai`i
Bathymetry and acoustic backscatter data of the Sacramento River, from the Feather River to Knights Landing, California in February, 2011
Gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California
San Francisco Bay Delta Bathymetric/Topographic digital elevation model (DEM) - 2016 SF Bay Delta DEM 10-m
High-resolution bathymetry and topography of south San Francisco Bay, California
Diverse tsunamigenesis triggered by the Hunga Tonga-Hunga Ha’apai eruption
Nearshore microfossil assemblages in a Caribbean reef environment show variable rates of recovery following Hurricane Irma
The role of surges during periods of very shallow water on sediment transport over tidal flats
Selective sediment transport during Hurricane Sandy on Fire Island (New York, USA): Inferences from heavy-mineral assemblages
Anthropogenic pollutants and biomarkers for the identification of 2011 Tohoku-oki tsunami deposits (Japan)
Morphodynamic resilience of intertidal mudflats on a seasonal time scale
Intertidal mudflats are morphodynamic features present in many estuaries worldwide. Often located between vegetated shores and deep channels they comprise valuable ecosystems and serve to protect the hinterland by attenuating waves. Although mudflats are persistently present on yearly to decadal time scales, little is known on their morphodynamic adaptation to short‐term variations in forcing such
The roles of flow acceleration and deceleration in sediment suspension in the surf zone
Sedimentary evidence of prehistoric distant-source tsunamis in the Hawaiian Islands
A revised continuous surface elevation model for modeling
Slough evolution and legacy mercury remobilization induced by wetland restoration in South San Francisco Bay
Organic geochemical investigation of far‐field tsunami deposits of the Kahana Valley, O'ahu, Hawai'i
Bed shear stress estimation under wave conditions using near-bottom measurements: Comparison of methods
Science and Products
- Science
Sediment Transport in Coastal Environments
Our research goals are to provide the scientific information, knowledge, and tools required to ensure that decisions about land and resource use, management practices, and future development in the coastal zone and adjacent watersheds can be evaluated with a complete understanding of the probable effects on coastal ecosystems and communities, and a full assessment of their vulnerability to natural...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.San Francisco Bay Bathymetry
Bathymetry of a dynamic tidal estuary, such as San Francisco Bay, provides the observable linkage between anthropogenic modifications of the landscape—such as evolving land use practices, flood control, and water diversions—and natural forces of climate-driven river flow, sea level change, tides, and wind. By examining our record of hydrographic surveys, spanning over 150 years, we can gain...San Francisco Bay geomorphology
The primary objective of this task is to develop tools for predicting the long-term geomorphic evolution of estuaries. Sediment core and historical change analysis will be used in combination with interpretation of high-resolution seismic profiles to develop tools for predicting geomorphic evolution of estuaries. Historical change analysis will use hydrographic and lidar data. Longer-term data...Tsunami Field Studies
Our tsunami scientists work on international teams to study the aftermath of tsunamis around the world, to gain a better understanding the impact of potential tsunamis on coastal communities of the United States. Their work helps inform local, state, and federal coastal planning, protection, and resiliency.Effects of Sea-Level Rise and Extreme Storms on California Coastal Habitats: Part 1
In California, the near-shore area where the ocean meets the land is a highly productive yet sensitive region that supports a wealth of wildlife, including several native bird species. These saltmarshes, mudflats, and shallow bays are not only critical for wildlife, but they also provide economic and recreational benefits to local communities. Today, sea-level rise, more frequent and stronger storUSGS Scientists in Samoa and American Samoa Studying Impacts of Tsunami in 2009
On September 29, 2009, an M 8.1 earthquake in the Samoa Islands region of the South Pacific Ocean caused a tsunami that resulted in 100's of lost lives. A rapid-response team of USGS scientists traveled to the Samoa Islands in October-November 2009 to collect time-sensitive data that would have been quickly degraded or destroyed by recovery activity and natural processes.Preliminary Analysis of Sedimentary Deposits from the June 23, 2001 Peru Tsunami
A Cooperative Study by the USGS, la Dirección de Hidrografía y Navegación de la Marina de Guerra del Perú, Instituto Geofísico del Perú, Instituto Geologico, Minero y Metalurgico, University of California, Santa Cruz, University of Southern California, and University of San Agustin. September 4 - September 18, 2001Preliminary Analysis of Sedimentary Deposits from the July 17, 1998 Papua New Guinea Tsunami
Preliminary analysis of sedimentary deposits from the tsunami caused by the July 17, 1998 Papua New Guinea earthquake. - Data
Bathymetric surveys collected near Dumbarton Bridge in south San Francisco Bay, California, 2008 to 2019
In 2008, the U.S. Geological Survey began mapping the main channel and shallow intertidal mudflats between the Dumbarton Bridge and a railroad bridge located 1 km to the south in south San Francisco Bay. This information was collected to document bathymetric change before and after restoration to inform the South Bay Salt Pond Restoration Project (https://www.southbayrestoration.org), which initiaObservations 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 County, CalifHigh-resolution (1 m) digital elevation model (DEM) of San Francisco Bay, California, created using bathymetry data collected between 1999 and 2020 (ver. 2.0, July 2021)
A 1-m resolution bathymetric digital elevation model (DEM) of all off San Francisco Bay was constructed from bathymetric surveys collected from 1999 to 2016. The DEM has been divided into northern and southern sections due to file size, and is available in both MLLW and NAVD88 versions. Background: In 2014 and 2015 the California Ocean Protection Council (OPC) contracted the collection of bathyPilot study on bathymetric change analyses in the Sacramento-San Joaquin Delta, California
The bathymetry of the Sacramento-San Joaquin Delta affects the flow of water and sediment throughout the system and is a basic control on levee stability, habitat distribution, and water quality. Delta bathymetry is dynamic, responding to both natural forces and human activities. Assessment of future Delta conditions is aided by understanding how its bathymetry has changed in the past. This pilotCore 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 as well asBathymetry and acoustic backscatter data of the Sacramento River, from the Feather River to Knights Landing, California in February, 2011
On February 1, 2011, the USGS Pacific Coastal and Marine Science Center (PCMSC) team carried out a project using interferometric sidescan sonar to characterize the riverbed and channel banks of a 12 mile reach of the Sacramento River near the town of Knights Landing, California (River Mile 79 through River Mile 91). The project was developed in coordination with David Smith, Engineering Research aGravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California
This data release contains information on gravity cores that were collected by the U.S. Geological Survey in the area of San Pablo Bay and Carquinez Strait, California in 1990, 1991, and 2000. Ten (10) pdf files describe gravity cores that were split, photographed, and imaged by X-rays, and another pdf file contains a core-log legend. In addition, a shapefile (sanpablo_spls.shp) provides sample coSan Francisco Bay Delta Bathymetric/Topographic digital elevation model (DEM) - 2016 SF Bay Delta DEM 10-m
A high-resolution (10-meter per pixel) digital elevation model (DEM) was created for the Sacramento-San Joaquin Delta using both bathymetry and topography data. This DEM is the result of collaborative efforts of the U.S. Geological Survey (USGS) and the California Department of Water Resources (DWR). The base of the DEM is from a 10-m DEM released in 2004 and updated in 2005 (Foxgrover and others, - Maps
High-resolution bathymetry and topography of south San Francisco Bay, California
This map consists of a view of the southern end of San Francisco bay with the water 'removed.' The image is overlain by a set of six figures: - Figure 1. Perspective view looking southeast down south San Francisco Bay. - Figure 2. Perspective view looking east with the Diablo Range in the distance. - Figure 3. Perspective view looking southwest over Bair Island toward Redwood City. - Figure 4. P - Publications
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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 volcanic eruptioNearshore microfossil assemblages in a Caribbean reef environment show variable rates of recovery following Hurricane Irma
Modern microfossil distributions reflect site-specific habitats and provide an opportunity to assess sediment transport pathways in the nearshore environment. When applied to overwash deposits in the geological record, they provide insight into sediment provenance and transport, factors important for understanding patterns of frequency and intensity of past storms and tsunamis. Modern distributionThe role of surges during periods of very shallow water on sediment transport over tidal flats
Periods of very shallow water (water depth in the order of 10 cm) occur daily on tidal flats because of the propagation of tides over very gently sloping beds, leading to distinct morphodynamical phenomena. To improve the understanding of the characteristics of velocity and suspended sediment concentration (SSC) surges and their contribution to sediment transport and local bed changes during perioSelective 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 laminations”) were oAnthropogenic pollutants and biomarkers for the identification of 2011 Tohoku-oki tsunami deposits (Japan)
Organic geochemistry is commonly used in environmental studies. In tsunami research, however, its applications are in their infancy and it is still rarely used. We present results for two types of organic geochemical markers, biomarkers and anthropogenic markers, present in deposits left by 2011 Tohoku-oki tsunami on the Sendai Plain, Japan. As the tsunami inundated the coastal lowland up to 4.85Morphodynamic resilience of intertidal mudflats on a seasonal time scale
Intertidal mudflats are morphodynamic features present in many estuaries worldwide. Often located between vegetated shores and deep channels they comprise valuable ecosystems and serve to protect the hinterland by attenuating waves. Although mudflats are persistently present on yearly to decadal time scales, little is known on their morphodynamic adaptation to short‐term variations in forcing such
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, acceleratingSedimentary evidence of prehistoric distant-source tsunamis in the Hawaiian Islands
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" (e.g., Alaska-Aleutian, Kuril-Kamchatka, Chile, and Japan). Mapping and dating anomalous beds of sand and silt deposited by tsunamis in low-lying areas along Pacific coasts, even those distant from subduction zones, is crA revised continuous surface elevation model for modeling
A digital elevation model (DEM) is an essential component of any hydrodynamic model. The Delta Modeling Section (Section) has maintained a database of bathymetry soundings and levee surveys for decades and published a 10-meter (10m) DEM for the San Francisco Bay and Sacramento-San Joaquin Delta (Delta) (California Department of Water Resources 2012). In collaboration with the U.S. Geological SurveSlough evolution and legacy mercury remobilization induced by wetland restoration in South San Francisco Bay
Coastal wetlands have a long history of degradation and destruction due to human development. Now recognized as one of the most productive ecosystems in the world, substantial efforts are being made to restore this critical habitat. While wetland restoration efforts are generally viewed as beneficial in terms of providing wildlife habitat and flood control, they are often accompanied by dramatic pOrganic geochemical investigation of far‐field tsunami deposits of the Kahana Valley, O'ahu, Hawai'i
Far‐field tsunami deposits observed in the Kahana Valley, O'ahu, Hawai'i (USA), were investigated for their organic‐geochemical content. During short high‐energy events, (tsunamis and storms) organic and chemical components are transported with sediment from marine to terrestrial areas. This study investigates the use of anthropogenic based organic geochemical compounds (such as polycyclic aromatiBed shear stress estimation under wave conditions using near-bottom measurements: Comparison of methods
Understanding the influence of waves on bed shear stress is critical for predicting morphodynamical behaviours in coastal areas. Near-bed flow was measured on the middle and lower intertidal mudflats along the Jiangsu coast, China, using a three-dimensional acoustic velocimeter that collected a 3.5-cm vertical profile at 1mm resolution and sample rate of 25 Hz. On the lower and middle tidal flats, - News
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