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2019 Geophysical surveys and sediment coring in southern Cascadia (northern California) Completed

By Pacific Coastal and Marine Science Center August 20, 2020

Geophysical data and sediment cores collected offshore of northern California in 2019, a USGS-BOEM partnership

An illustrative map of the seafloor off of California with ship tracklines and dots to show coring locations.
Sources/Usage: Public Domain. Visit Media to see details.
2019 Geophysical surveys and sediment coring in southern Cascadia (northern California)

These surveys are part of the USGS project, “Cascadia Subduction Zone Marine Geohazards.”

Objectives

The sediment sampling and geophysical surveys were designed to address questions regarding tectonic activity and sediment dispersal patterns across the margin. Survey tracks and sampling sites were targeted to investigate the Eel River forearc basin sedimentation history and the sources and pathways of sediment gravity flows, both of which provide context for interpreting the deep-sea turbidite record. In addition, these data will provide key information for understanding the earthquake history of active structures in southern Cascadia.

Participants

USGS Scientists: Jenna Hill (PI), Janet Watt, Danny Brothers, Nora Nieminski, Gerry Hatcher, Brandon Nasr, Pete Del Ferro, Jenny and UCSC Student: Travis Alonghi (Photo 7)

Partners

Bureau of Ocean and Energy Management (BOEM)

Platform Used

M/V Bold Horizon

A group of people stand, smiling for the camera, on the deck of a ship at sea with the Golden Gate Bridge in the background
Sources/Usage: Public Domain.
Photo 7: USGS scientists on the stern (back deck) of M/V Bold Horizon in San Francisco Bay: (back row, standing, left to right) Brandon Nasr, Danny Brothers, Travis Alonghi (USGS student contractor), Gerry Hatcher, Jenna Hill, Pete Dal Ferro, and Jenny McKee; and (front row, kneeling, left to right) USGS scientists Janet Watt and Nora Nieminski.

Data Collected

Jumbo piston/gravity sediment cores (Photos 1-5), Sparker multi-channel seismic (MCS), Chirp sub-bottom profiler (Photo 6)

Highlights

  • >2,100 km of Chirp sub-bottom and sparker multi-channel seismic data collected
  • ~40 sediment cores (3-7 m in length) recovered

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

A man and woman work on a steel core on the deck of a ship.
Sources/Usage: Public Domain.
Photo 1: USGS scientists Pete Dal Ferro and Jenny McKee securing a recently collected jumbo piston core (JPC) on the back deck of M/V Bold Horizon for preliminary core processing.
A smiling woman holds onto a sediment core.
Sources/Usage: Public Domain.
Photo 2: USGS Mendenhall postdoc Nora Nieminski showing some love for a trigger core recovered from the Cascadia subduction zone.
A smiling woman holds a spring-loaded instrument against a sediment core.
Sources/Usage: Public Domain.
Photo 3: USGS scientist Janet Watt making a shear vane measurement on a gravity core to understand how the seafloor responds to earthquake shaking.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

People work on the deck of a ship securing a long coring device.
Sources/Usage: Public Domain.
Photo 4: USGS scientists Nora Nieminski, Jenna Hill, and Brandon Nasr working to cap and secure a trigger core on deck. Trigger cores can provide important information about seafloor sediments just below the seafloor.
Four people stand around a coring device on the deck of a ship.
Sources/Usage: Public Domain.
Photo 5: USGS scientists Brandon Nasr, Jenna Hill, Nora Nieminski, and Jenny McKee removing a sediment-filled core liner from the jumbo piston core barrel with the picturesque northern California coastline in the background.
Two men on the deck of a ship stand near a sonar device readying it for deployment.
Sources/Usage: Public Domain.
Photo 6: USGS student contractor Travis Alonghi and USGS scientist Danny Brothers deploying the Chirp sub-bottom profiler at sunset from M/V Bold Horizon.
  • Overview

    Geophysical data and sediment cores collected offshore of northern California in 2019, a USGS-BOEM partnership

    An illustrative map of the seafloor off of California with ship tracklines and dots to show coring locations.
    Sources/Usage: Public Domain. Visit Media to see details.
    2019 Geophysical surveys and sediment coring in southern Cascadia (northern California)

    These surveys are part of the USGS project, “Cascadia Subduction Zone Marine Geohazards.”

    Objectives

    The sediment sampling and geophysical surveys were designed to address questions regarding tectonic activity and sediment dispersal patterns across the margin. Survey tracks and sampling sites were targeted to investigate the Eel River forearc basin sedimentation history and the sources and pathways of sediment gravity flows, both of which provide context for interpreting the deep-sea turbidite record. In addition, these data will provide key information for understanding the earthquake history of active structures in southern Cascadia.

    Participants

    USGS Scientists: Jenna Hill (PI), Janet Watt, Danny Brothers, Nora Nieminski, Gerry Hatcher, Brandon Nasr, Pete Del Ferro, Jenny and UCSC Student: Travis Alonghi (Photo 7)

    Partners

    Bureau of Ocean and Energy Management (BOEM)

    Platform Used

    M/V Bold Horizon

    A group of people stand, smiling for the camera, on the deck of a ship at sea with the Golden Gate Bridge in the background
    Sources/Usage: Public Domain.
    Photo 7: USGS scientists on the stern (back deck) of M/V Bold Horizon in San Francisco Bay: (back row, standing, left to right) Brandon Nasr, Danny Brothers, Travis Alonghi (USGS student contractor), Gerry Hatcher, Jenna Hill, Pete Dal Ferro, and Jenny McKee; and (front row, kneeling, left to right) USGS scientists Janet Watt and Nora Nieminski.

    Data Collected

    Jumbo piston/gravity sediment cores (Photos 1-5), Sparker multi-channel seismic (MCS), Chirp sub-bottom profiler (Photo 6)

    Highlights

    • >2,100 km of Chirp sub-bottom and sparker multi-channel seismic data collected
    • ~40 sediment cores (3-7 m in length) recovered

    ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

    A man and woman work on a steel core on the deck of a ship.
    Sources/Usage: Public Domain.
    Photo 1: USGS scientists Pete Dal Ferro and Jenny McKee securing a recently collected jumbo piston core (JPC) on the back deck of M/V Bold Horizon for preliminary core processing.
    A smiling woman holds onto a sediment core.
    Sources/Usage: Public Domain.
    Photo 2: USGS Mendenhall postdoc Nora Nieminski showing some love for a trigger core recovered from the Cascadia subduction zone.
    A smiling woman holds a spring-loaded instrument against a sediment core.
    Sources/Usage: Public Domain.
    Photo 3: USGS scientist Janet Watt making a shear vane measurement on a gravity core to understand how the seafloor responds to earthquake shaking.

    ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

    People work on the deck of a ship securing a long coring device.
    Sources/Usage: Public Domain.
    Photo 4: USGS scientists Nora Nieminski, Jenna Hill, and Brandon Nasr working to cap and secure a trigger core on deck. Trigger cores can provide important information about seafloor sediments just below the seafloor.
    Four people stand around a coring device on the deck of a ship.
    Sources/Usage: Public Domain.
    Photo 5: USGS scientists Brandon Nasr, Jenna Hill, Nora Nieminski, and Jenny McKee removing a sediment-filled core liner from the jumbo piston core barrel with the picturesque northern California coastline in the background.
    Two men on the deck of a ship stand near a sonar device readying it for deployment.
    Sources/Usage: Public Domain.
    Photo 6: USGS student contractor Travis Alonghi and USGS scientist Danny Brothers deploying the Chirp sub-bottom profiler at sunset from M/V Bold Horizon.