The National Geoelectromagnetic Facility at Oregon State University ( operates what is currently the world's largest pool of land-based magnetotelluric instruments. For more information on the NGF and its instruments and services, contact the NGF Director, Dr. Adam Schultz through the email address:

Researchers at Oregon State University as well as researchers at other institutions in the US and abroad make use of the NGF's instruments for a variety of long-period and wideband magnetotelluric surveys. These can range from focussed surveys aimed at resource exploration; work in CO2 sequestration and reservoir management; geothermal research; groundwater research; studies of volcanic and hydrothermal systems, as well as larger-scale 3-D geological mapping purposes. Increasingly the NGF facility's instrumentation has also been used for purposes related to mitigating damage to the electric power grid from space weather.

Some of the stories about our own projects, as well as projects of other investigators supported by the NGF's instruments can be found on this page.


1) The EarthScope Project

From 2006 to 2018, Oregon State University was the subawardee of NSF and IRIS, responsible for the EarthScope Magnetotelluric Program. OSU installed and operated 7 BackBone MT stations - ultra long-period MT stations installed in 2-m deep underground vaults with solar power and state-of-health telemetry. The goal of the Backbone MT project was to provide MT impedance data that extended into the period band of 10,000 s - 100,000 s, which served to provide deep "anchor points" to the continental scale EarthScope MT Transportable Array.

OSU operated the MT Transportable Array from 2006 - 2018, ultimately installing over 1100 MT stations spanning roughly 2/3 of the conterminous US (CONUS). The MT TA stations were typically operated for (nominally) 3-weeks, providing MT response functions in the period band of 10 s - 10,000 s.


2) MT Array

The systematic mapping of the 3-D geoelectrical structure of CONUS continued in 2019 and 2020 under NASA support, starting with the completion of Southern California and parts of Southern Nevada. From 2019 onward, this activity is referred to as MTArray to reflect the change in funding source and the continuation of this activity in 2020 and beyond through a cooperative agreement between USGS and OSU. We currently project that we'll complete mapping the conterminous USA by mid-2024. To see an up-to-date map of MT Array stations and the status of each station, please follow the MTArray link on this web site's homepage.