Updates:

Project updates, including ongoing and past at-sea and community activities associated with the Near-Trench Geodetic Experiment

Future PI training (May 2025):

Are you a researcher who would like to break into seafloor geodesy? Please consider participating in a workshop that is designed to prepare new investigators to design and propose a seafloor geodetic experiment.

Target Audience: any researcher new to seafloor geodesy, with an emphasis on early career researchers

When: Sunday May 18, immediately preceding the 2025 NSF SAGE/GAGE Community Science Workshop

Where: Radisson Blu Mall of America, Bloomington, Minnesota

Travel Support: Limited travel and lodging support is available.

How to apply: Complete the application form by March 14th. We expect to be able to accommodate 20 individuals.

Learning Goals:

Gain the background knowledge to write a competitive seafloor geodetic proposal
Understand the signal-to-noise considerations for experimental design and hypothesis testing
Be able to construct a budget for a seafloor geodetic experiment
Gain familiarity with ship logistics and planning
Understand the design and specifications of seafloor geodetic instrumentation
Network with other researchers who share common interests

2024 Field Deployments:

Between Jun 19 and July 11, 2023 we set off on two field expeditions to instrument Alaska and Cascadia with more seafloor geodetic equipment. The two overlapping expeditions meant that we split up PI teams, technicians, and Apply-2-Sail crew for the efforts.

In total, we deployed 6 new 3-transponder arrays in Alaska extending from Kodiak Island to Unalaska Island in he Aleutians, and reinstrumented 2 existing arrays in Cascadia, each with 3 new transponders that have fresh battery packs. With the deployments, we set out two community Wave Gliders to do the heavy lifting of surveying the sites through late September.

Daily updates of our activities can be checked out on our blog.

Beyond the Community Experiment, two other PI-driven projects were being undertaken:

In Alaska, near the area of a devastating tsunami earthquake, a novel dense mesh network of 10 deep-water transponders were deployed with a new Wave Glider outfitted for such deep measurements (using lower frequency acoustics). This effort is led by Andy Newman.
In Cascadia, we serviced a seafloor fiber-optic cable that is making measurements of strain across the local environment. This effort, led by Noel Jackson, is in the hunt for offshore slow slip events.

Apply to Sail 2023:

July 13, 2023: The 2023 Cascadia deployment just completed. The at-sea field work was a great success. You can follow activities at our blog. We had limited internet at sea, so some blog entries will be added following our trip.

The apply to sail for 2023 has completed, but keep your eyes open for another opportunity next year.

GNATSS software update:

July 1, 2023: The project-funded GNSS Acoustic Transponder Surveying Software (GNATTS), is well underway!!

We have begun creating an open-source version of a GNSS-Acoustic processing package for the community. The software is currently being updated in partnership with Don Setiawan of the Scientific Software Engineering Center at UW’s eScience Institute. The core computation is now updated from Fortran to work within a Python based architecture. This resulted in a 30% speedup in processing.

Additionally, the updated data format (from text to csv) has resulted in interoperability wins for the GNSS-A community. The final software package will be curated by John DeSanto.

With initial release expect another update with a direct link to the GitHub repository.

Planned and operational GNSS-Acoustic sites in Cascadia: previously deployed sites (white triangles), community experiment sites established and surveyed in 2022 (orange triangles) and sites planned for completion and surveying in 2023 (red circles)

Summer 2022

In July, UC San Diego, Univ. Washington, and Univ. Kansas participated in a research expedition on the R/V Thomas Thompson to begin deploying instrumentation for the community experiment. Over the course of 9-days they deployed 11 of the GNSS-Acoustic transponders from the community instrument pool, establishing 3 of the six sites proposed off shore Oregon (orange triangles at left) and partially installing a 4th site (NSS1). They also deployed the JASON ROV to reoccupy concrete benchmarks at the existing site NNP1 using legacy equipment from previous GNSS-Acoustic experiments in the region.

In addition to the above, they deployed one of the instrument pool Wave Gliders to collect positions at all of these sites. The Wave Glider collected two data sets at each of the new sites: a set of acoustic ranges from a circular drive* around each of the individual transponders and a set of acoustic ranges from the center of each transponder array. The survey from the array center collected range data for transponder-triads simultaneously and allowed for initial array-center positioning with cm-level uncertainty, the first data points in the position time series for each of the new sites.

A follow-up expedition is currently planned for July 2023, during which we plan to install the remaining sites in the off shore Cascade region (NSS1, NQU1, and NLP1). At this time we will also deploy a Wave Glider to collect positions at each site in the array.

We are still awaiting shiptime for field activities of Alaska. This may not happen until 2024.

* The circular drives allow us to approximately triangulate the initial positions of each transponder with an uncertainty of 10-20 cm, which is good enough to correct for any distance the transponders may have drifted from their drop points as they sank through the water column