Earth and Environmental Sciences Area Logo Earth and Environmental Sciences Area Logo
Lawrence Berkeley National Laboratory Logo
Menu
  • About Us
    • Contact Us
    • Organizational Charts
    • Virtual Tours
    • EESA Strategic Vision
  • Our People
    • A-Z People
    • Alumni Network
    • Area Offices
    • Committees
    • Directors
    • IDEA Working Group
    • Paul A. Witherspoon
    • Postdocs & Early Careers
    • Search by Expertise
  • Careers & Opportunities
    • Careers
    • Intern Pilot w/CSUEB
    • Mentorship Program
    • Recognition & Funding Opps
    • EESA Mini Grants
    • S&E Metrics for Performance and Promotion
    • Student Opportunities
    • Supervisor EnRichment (SupER) Program
    • Promotion Metrics (Scientific)
  • Research
    • Area-Wide Program Domain
      • Earth AI & Data
    • Our Divisions
    • Climate & Ecosystem Sciences Division
      • Environmental & Biological Systems Science
        • Programs
        • Environmental Remediation & Water Resources
        • Ecosystems Biology Program
        • Bioenergy
      • Biosphere-Atmosphere Interactions
        • Programs
        • Climate Modeling
        • Atmospheric System Research
        • Terrestrial Ecosystem Science
      • Climate & Atmosphere Processes
        • Programs
        • Climate Modeling
        • Atmospheric System Research
      • Earth Systems & Society
        • Programs
        • Climate Modeling
    • Energy Geosciences Division
      • Discovery Geosciences
        • Programs
        • Basic Energy Sciences (BES) Geophysics
        • Basic Energy Sciences (BES) Geochemistry
        • Basic Energy Sciences (BES) Isotope
      • Energy Resources and Carbon Management
        • Programs
        • Carbon Removal & Mineralization Program
        • Carbon Storage Program
        • Geothermal Systems
        • Hydrocarbon Resource Sustainability
        • Nuclear Energy & Waste
      • Resilient Energy, Water & Infrastructure
        • Programs
        • Water-Energy
        • Critical Infrastructure
        • Environmental Resilience
        • Grid-Scale Subsurface Energy Storage
        • National Alliance for Water Innovation (NAWI)
    • Projects
    • Research at a Glance
    • Publication Lists
    • Centers and Resources
    • Technologies & National User Programs
  • Departments
    • Climate Sciences
    • Ecology
    • Geochemistry
    • Geophysics
    • Hydrogeology
    • Operations
  • News & Events
    • News
    • Events
    • Earth & Environment Newsletter
  • Intranet
  • Safety
    • EESA Safety
  • FoW
  • Search

  • all
  • people
  • events
  • posts
  • pages
  • projects
  • publications

Field Access Allows First-Ever Geothermal Basin Characterization Using Dark Fiber5 min read

by Christina Procopiou on December 16, 2020

Energy Geosciences Division

We are thankful to have received approval to do limited field work as Berkeley Lab continues working under COVID-19 requirements. As an example, last month research scientist Verónica Rodríguez Tribaldos along with Michelle Robertson and Todd Wood of the Geosciences Measurement Facility deployed a distributed acoustic sensing (DAS) system on a “dark fiber” at a telecommunication Intermediate Line Amplification hut in Calipatria, California. The purpose is to explore the potential for DAS in characterizing geothermal systems at the basin scale. 

The project, a collaboration across several Berkeley Lab divisions (Energy Geosciences, Computing Sciences, and ESnet), universities (Rice University, UC San Diego), and national laboratories (Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory) is particularly targeting so-called “hidden” geothermal resources which cannot be observed directly at Earth’s surface. 

Verónica, a geologist and geophysicist by training, applies expertise in DAS and classic seismic techniques to advance imaging of Earth’s subsurface. She talked with us about the work in Calipatria and how it can make an impact on the sourcing of clean energy from underground geothermal reservoirs. With better understanding of the subsurface, scientists can improve technologies for extracting geothermal energy from deep underground — which has the potential to power 100 million American homes. 

Q: What is dark fiber, and what does it have to do with your fieldwork?

A: This fieldwork was for our project “Imperial Valley Dark Fiber Project,” funded by the Department of Energy Geothermal Technologies Office (GTO). The main objective of this project is to explore the use of fiber optic sensing, and in particular distributed acoustic sensing (DAS), to characterize geothermal systems at the basin scale in Imperial Valley, Southern California. 

DAS is a novel, photonic-based sensing technology that repurposes standard telecommunication fiber-optic cables as arrays of thousands of strain-rate sensors, enabling measuring seismic vibrations at spatial samplings of 1 m or less along distances of several 10s of kilometers. DAS systems can be deployed on so-called “dark fibers” which are existing, telecommunication fiber-optic cables that are not being used for data transfer. By connecting these fibers to a DAS system, they can be repurposed as sensing arrays, enabling efficient acquisition of high-resolution seismic data.

The fieldwork that we conducted in the Imperial Valley consisted of deploying a DAS system on one of these “dark fibers” at a telecommunication Intermediate Line Amplification (ILA) hut in the town of Calipatria. This dark fiber runs near an active geothermal area, and crosses several tectonically-interesting areas with structures that potentially control the geothermal system. The array will be used to continuously acquire high-resolution seismological and geodetic data for several months, which can help characterize these subsurface structures as well as surface deformation associated with the active geothermal area.

Q: What exactly are you looking to measure using DAS?

A: The purpose of this experiment is to use DAS deployed on dark fiber to record ambient seismic noise generated by vehicles, trains, etc. that can be analyzed to build high-resolution subsurface velocity models. These models can be used to characterize the tectonic features linked to the geothermal system, and can also help identify anomalies related to “hidden” resources that do not have a surface expression. We will also be recording local and regional earthquakes linked to tectonic processes and possibly geothermal operations. We are also hoping that the same DAS data can be analyzed to map surface deformation associated with the geothermal system. 

Q: How extensive of an area are you hoping to assess?

A: The reach of our system is about 28 km from Calipatria southwards, crossing the Brawley Seismic Zone and running very close to the North Brawley Geothermal Power Plant. We are recording data at a spatial sampling of 4 meters, which gives us over 6,000 measurement points along the array. 

Q: What is the real-world impact of the research?

A: At present, large portions of Western basins associated with geothermal resources remain poorly understood. One of the main reasons is the challenges associated with acquiring high-resolution geophysical data at regional scales, including high costs of active seismic surveys and long-term deployments and the limited coverage of dense arrays. The sparse spacing of permanent seismic stations also result in a high minimum seismic magnitude threshold for detecting natural and induced seismicity associated with hidden and existing geothermal fields. These factors can result in a lack of understanding of regional structures relevant to geothermal prospecting, as well as in missed resources. 

DAS is a very promising technique for high-resolution, basin-scale imaging, as it enables acquisition of seismic data along a single fiber out to 30 km at spatial densities of a few meters, providing over 15,000 measurement points. Moreover, using dark fibers eliminates the challenges of sensor deployment and provides a cost-effective way of acquiring regional, high-resolution seismic datasets. Our study area in Imperial Valley, combines a complex geologic context with extensive existing and hidden geothermal systems, which makes it an excellent site to test this technology. A key target in our project is to use DAS on dark fiber to image highly faulted zones which might provide conduits for deep hydrothermal fluid migration, and zones of lower seismic velocity at depth  that could provide a signature for hidden reservoirs. Moreover, we intend to process our passive seismic data to investigate microseismicity associated with these systems. By the end of the project, we hope to have a better understanding of this active geothermal area and of the utility of DAS and dark fiber as a tool for geothermal exploration and monitoring. 

More information about the project is available here and here. 

News & Events

EESA Research Scientist Selected for NAE 2022 U.S. Frontiers of Engineering Symposium2 min read

May 23, 2022

Mengsu Hu, an EESA research scientist, was selected to participate in the National Academy of Engineering (NAE) U.S. Frontiers of Engineering symposium in September. For more than 25 years, the NAE has identified the best and brightest early-career engineers from large and small companies, research universities, and government laboratories to discuss their leading-edge research and…

Microbial Response to a Changing and Fire-Prone Arctic Ecosystem2 min read

April 27, 2022

Burning more than 1,000 square kilometers of tundra on Alaska’s North Slope, the 2007 Anaktuvuk river wildfire is one of the largest fires to occur within Arctic ecosystems. Berkeley Lab scientist Nick Bouskill led a study that used data from this disturbance event to predict ecosystem recovery as fires advance in a changing climate. (Credit:…

Study Evaluates Phosphorus Availability Underground using Plant Leaves as Biosensors3 min read

April 25, 2022

When envisioning renewable energy, sources that often come to mind are the sun, wind, batteries, and water. However, biofuel, a type of renewable energy that converts organic material from plants into liquid fuel, is an important part of a global effort to achieve net-zero emissions. Switchgrass, a deep-rooted native North American grass that grows in…

EESA Multimedia Producer and Digital Strategist Niba Audrey Nirmal Awarded Ocean Science Journalism Fellowship1 min read

Niba Audrey Nirmal, EESA Multimedia Producer and Digital Strategist, has been awarded the Woods Hole Oceanographic Institute (WHOI) Ocean Science Journalism (OSJ) Fellowship.   In May, Nirmal will join nine other selected fellows on a five-day, experiential-learning based retreat at the WHOI located in Falmouth, Massachusetts to learn about ocean-science concepts ranging from marine biology to…

  • Our People
    • Area Offices
    • Committees
    • Directors
    • Organizational Charts
    • Postdocs
    • Staff Only
    • Search by Expertise
  • Departments
    • Climate Sciences
    • Ecology
    • Geochemistry
    • Geophysics
    • Hydrogeology
  • Research
    • Climate & Ecosystem Sciences Division
    • Energy Geosciences Division
    • Program Domains
      • Programs
    • Projects
  • Contact
    • 510 486 6455
    • eesawebmaster@lbl.gov
    • Our Identity

Earth and Environmental Sciences Area Logo DOE Earth and Environmental Sciences Area Logo UC

A U.S. Department of Energy National Laboratory Managed by the University of California

Lawrence Berkeley National Laboratory · Earth and Environmental Sciences Area · Privacy & Security Notice