Update on the NSF SAGE MT Facility - New Instruments, Software Resources, and Training Opportunities

IRIS is pleased to provide an update on the acquisition of portable magnetotelluric (MT) instruments and our ongoing development of new resources for MT Principal Investigators (PIs). This work is supported by the National Science Foundation as part of the NSF SAGE facility, operated by IRIS and its partners.

Instrumentation for Portable Deployments
The PASSCAL Instrument Center (PIC) has 12 new LEMI-424 long-period MT systems ready for community use. These easy-to-deploy, low-power MT systems observe low frequency variations of the Earth's electric and magnetic fields, enabling PIs to produce 3D characterization of the electrical properties of the crust and upper mantle at local to regional scales. These capabilities are equivalent to those exhibited as part of EarthScope's MT surveys. The LEMIs are available right now, with special enclosures available to facilitate the ease of transport and deployment. In addition, all PIs using LEMI-424 systems are eligible to receive complimentary use of the KMS-200 data processing software package for one-year as part of a licensing agreement with KMS. PASSCAL also provides software and training to archive data and metadata for these instruments with the NSF SAGE Data Management Center (DMC).

We are especially excited to announce our procurement plan for wide-band MT instrumentation. IRIS will obtain a total of fourteen Phoenix MTC-5C data acquisition systems over the course of 2021. These will be available with magnetic induction coils from Phoenix (MTC-150 and MTC-180) and Zonge (ANT-4 and ANT-7). Although both are well-suited for long-period and wide-band (high frequency) surveys, this variety of coils offers versatility to PIs and is consistent with the PIC's tradition of supporting multiple types of interoperable geophysical instrumentation. PIs will have access to the EMPower processing suite for in-field analyses, and PASSCAL will establish similar "dirt-to-desktop" resources in 2021/2022 for ensuring that PIs can seamlessly archive data from their experiments in the NSF SAGE DMC.

Data Formatting and Processing Tools
IRIS is also working with a software developer and collaborators at the USGS to produce tools to author MTH5, an HDF5-based format for locally storing and exchanging MT datasets, and a rewrite of the EMTF codebase (originally authored by Gary Egbert) into a modular, open-sourced, Python-based software called Aurora. These tools will be available to any users this fall. MTH5 adheres to new MT metadata standards developed by the US MT community.

Engaging Potential Users
Finally, we encourage interested PIs to include MT in their funded experiments and future proposals. We are planning several community outreach opportunities over the next year targeting potential new users. On Wednesday, August 18, during the GAGE/SAGE community science workshop, please consider attending a 75-minute professional development minicourse “Everything You Need to Know About Proposing to Use PASSCAL MT Instrumentation for Your Science” that presents the PIC’s MT facility and PI-support capabilities, highlights examples of common usage cases for MT instruments, and provides a panel discussion on including MT in proposals to NSF. In December, PIC staff are planning a half-day in-person workshop associated with AGU to provide hands-on look at MT instruments. Finally, early next summer, we intend to hold a week-long training course for operating MT instruments and performing first-order processing and analyses of these data.

If you have additional questions about opportunities for using NSF's NSF SAGE facility for conducting MT research, please do not hesitate to ask.

Andy Frassetto (IRIS, MT Program Manager)
Ninfa Bennington (USGS, Chair-EM Advisory Committee)