VLF Data

View summary plots of selected VLF data or view charts showing the availability of data across the entire data set. These summary images are publicly available and no login is necessary.
Daily Data Summary
View Data Summary Plots
Daily Data Summary
View Data Availability Charts
Search for raw VLF broadband or narrowband data. Registration is required to download the raw data files.
Search Raw Broadband Data
Download Raw Broadband Data
Search Raw Narrowband Data
Download Raw Narrowband Data

Data Types and Formats

The VLF Group collects data from ground stations located across the globe. There are two principle types of data collected, broadband and narrowband. Broadband data is full waveform data sampled at 100 kHz (frequency range of 300 Hz to 40 kHz). Narrowband data refers to the demodulated amplitude and phase of narrowband VLF transmitters. Both broadband and narrowband data is typically collected on two orthogonal antennas oriented in the North/South and East/West directions.
All raw data is stored in Matlab Version 4 format. Detailed information on reading and plotting the data can be found here.

Data Usage Policy

The VLF Group is committed to the free flow of scientific data and supports a fully open data policy. We request to be given the chance to participate in any studies for which these data are helpful and to participate in publications. At a minimum, we request that you inform us before you publish these data or present them at a meeting or to the public. The data are provided "as is" and so have known instrumental effects and "bugs". We are willing to provide calibration information and to fulfill reasonable requests to produce customs plots of the data. Please contact us with any questions regarding the data and its interpretation.


The online availability of the Stanford University VLF Group data set has been made possible by a grant from the Office of Naval Research under the Defense University Research Instrumentation Program (DURIP). The collection of this data is supported by a set of grants from the Office of Naval Research (ONR), the National Science Foundation (NSF), and the National Aeronautics and Space Administration (NASA).
IHY - Stanford - UN - NASA


About the VLF Group

The Stanford University VLF Group investigates the Earth's electrical environment, its upper atmosphere, Whistler lightning discharges, radiation belts, and the ionized regions of the earth's upper atmosphere known as the ionosphere and magnetosphere. Much of our work involves the use of very low frequency (VLF) electromagnetic waves which are generated by lightning discharges, by man-made transmitters and by the energetic radiation belt electrons. We use VLF waves as diagnostic tools to investigate physical processes in the vicinity of the Earth's low and high altitude plasma environment. Under the direction of Professor Umran Inan, the VLF group carries out extensive observational programs at multiple sites across the world on all seven continents.
Earth's Magnetic Field