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Here are some of the articles that have been recently posted to the PASSCAL website:

SmartSolo archives flipped polarity (IGU-16HR 3C 5Hz)

Dear EarthScope Community and EPIC PIs:

In September of 2023 we discovered that SmartSolo node (IGU-16HR 3C, 5Hz) data archived from EPIC experiments has a non-standard polarity on the Z-channel relative to the down-positive industry geophone convention. Details of this discovery and the steps that will be taken to correct this discrepancy, which will affect the existing and future archives, are outlined below.

Issue

The expected polarity for data archived from EPIC experiments are as follow:

Broadband seismometer – Up (Z-dip = -90), North and East motion produce a positive polarity. Geophone – Down (Z-dip = +90), North and East motion produce a positive polarity

Data archived, both PH5 and SEED, prior to October 05, 2023 from EPIC experiments using the SmartSolo nodes have the following polarity and metadata mismatch: 

12/04/2023
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Important Hardware/Software Notes for Researchers Using EPIC Equipment

This page includes important Hardware/Software Notes for Researchers Using EPIC Equipment. January 17, 2019: GPS Rollover

Late 2018 EPIC learned of a GPS week rollover event that can affect data logger performance and timing. EPIC has acquired a GNSS signal generator that can emulate GPS satellite signals. This satellite emulator allows us to test EPIC equipment that relies on GPS timing and to determine how equipment will handle the GPS rollover event. To date, we have determined that some models of GPS engines are affected by the rollover. How the rollover errors manifest is dependent on the data logger’s model and firmware version of the GPS engine.

01/17/2019
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Documentation - How to Archive your Active Source Data

Refer to the documentations below to learn how to prepare the data you've collected for archiving.  EPIC supports PH5 and SEGY as the archival data formats of active-source data sets.

Data from PH5 format data sets archived at the DMC can be accessed via PH5 Web Services.

07/31/2026
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Short-Period Sensors

Short-period Sensors: Sercel  L-22 Features:

Short-period sensors are rugged three-component seismometers that cover the frequency band from 1 Hz to 100 Hz. These sensors are used in both passive and active-source experiments. PASSCAL's short-period sensors can be either feedback seismometers requiring power or conventional, passive seismometers requiring no external power.

07/29/2026
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Dataloggers

A datalogger (also know as data acquisition system) is piece of electronic equipment which converts an input into a digital time series representation. Immense care should be taken when setting up and programming a datalogger. It is highly recommended that only experienced users program their own dataloggers and all others should consult a staff member for assistance.

While specific procedures and programming details will vary between the various types of dataloggers, there are several things that hold true when working with any datalogger.

The datalogger should be:

07/28/2026
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GNSS/GPS Receivers

Global Navigation Satellite System (GNSS) receivers sense incoming signals from the USA’s Global Positioning System (GPS) satellites and other constellations (GLONASS, Galileo, BeiDou, etc.). With signals from four or more satellites, the receivers use trilateration to determine a position.

07/22/2026
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Magnetotelluric Systems at EPIC

Magnetotelluric (MT) methods are used to produce conductivity models of the crust and upper mantle through the recording of geoelectric and geomagnetic field variations at the Earth's surface. Depending on the period of the recordings, these methods can provide results from a few hundred meters depth (short period) to 30 km or deeper (long period). Conductivity is a physical property, which is complementary to seismic velocity, and which is very sensitive to the presence of fluids. When seismic and MT data sets are measured together, the additional data can dramatically improve determinations of the structure of the crust and mantle.

 

 

Since 2019, the EPIC has been developing MT resources to meet PIs needs. We currently have a wide pool of MT equipment including both long-period (LEMI) and wideband (Phoenix) systems.

 

07/22/2026
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Polar Programs

 

The EPIC currently supports approximately 60 experiments per year worldwide, with 5-10% currently funded by the National Science Foundation (NSF) Office of Polar Programs (OPP). Polar projects commonly require a level of support that is several times that of seismic experiments in less demanding environments inclusive of very remote deployments (e.g. Tibet). 

The primary focus of the EPIC's Polar support efforts are:

07/21/2026
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General Information

Welcome to the EPIC General Information web pages. Here you will discover how to borrow EPIC equipment, learn about the equipment and services we provide, and browse past, current and future experiments scheduled to use our facility.

Borrowing Equipment Equipment Inventory Experiment+Schedules Training Shipping Information Governing Policies PI Instrumentation Advisory Committee Contacts Acknowledgment, Citation, and Logos Employment at EPIC
07/21/2026
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Acknowledgment & Citation

Acknowledgment

In any publications or reports resulting from the use of these instruments, please include a statement in the acknowledgment section. You are also encouraged to acknowledge NSF and EPIC in any contacts with the news media or in general articles.

How to Cite EPIC support in Your Publication

07/21/2026
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