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: 

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.

Dataloggers

A datalogger (also know as data acquisition system or DAS) 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 EPIC 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:

Accelerometers

EPIC Accelerometers: Titan Accelerometer Features:

Strong-motion sensors are accelerometers, and are designed to measure the large amplitude, high-frequency seismic waves typical of large local earthquakes. These seismic waves result in the strong ground motion we feel during a large earthquake. Strong ground motion is often to blame for the structural damage that occurs during an earthquake. The data seismologists record with strong motion sensors is used to improve the design of earthquake resistant buildings and to understand earthquake-induced geologic hazards like liquefaction and landslides. The range of motions of interest for strong-motion applications includes accelerations from 0.001 to 2 g and frequencies from 0 to 100 Hz or more.

Related categories:

Batteries

Batteries are PI Supplied.

Batteries come in two main types, primary which are single use and secondary which are rechargeable.

Related categories:

Controlled Sources

The Propelled Energy Generator, model: PEG-40Kg

RefTek RT 130 Datalogger

The RT130 is a 3 or 6 channel high resolution datalogger. It is low power and highly configurable for a wide range of applications and sensors. It is housed in a plastic clamshell-style enclosure which is nearly waterproof and has internal data storage in the form of two compact flash cards. The RT130 can simultaneously record to the CF cards and transmit data in near-realtime using either ethernet or serial based telemetry. It has built-in sensor controls, scheduled mass recentering, and calibration functions. The RT130 is programmed with a PalmOS program called PFC-130 via the serial port.

Features: