Active Experiments

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: 

EPIC pre-AGU Workshop

EPIC Workshop: Data Archiving and More!

Sunday, December 13, 2015
San Francisco - Zelos Hotel

Presentations are now online!  All are PDFs and the PH5 posters are a .gif and a .pdf

Session 1 - SEED Data Archiving

Session 2 - Instrument Responses (given by Mary Templeton of the EarthScope DMC)

Session 3 - PH5 tools and future plans

PH5 poster from AGU 2013

Frequently Asked Questions Regarding Data Requests from PH5 Data Sets

Here are frequently asked questions regarding data requests from PH5 data sets archived at the EarthScope DMC.  The answers are based upon the perspective the user is at the Data Request Form, which is available for each PH5 data set via its "Request" link found on the PH5 data set web page of the EarthScope DMC website.

1. How do I select the length of the record?

Related categories:

EPIC SEG-Y Trace Header

 EPIC SEG-Y utilizes big endian byte order and sets the various trace headers as outlined below.

 

EPIC SEG-Y Trace Header

 

Controlled Sources

The Propelled Energy Generator, model: PEG-40Kg

Currently, the only controlled active source available from EPIC is the PEG 40Kg Propelled Energy Generator, manufactured by R.T. Clark Companies, Inc. EPIC has purchased its first fully automated PEG-40Kg system in 2011. The system is light weight, and highly portable, and is designed to easily mount onto a truck or SUV hitch. Seismic energy is produced when  a large hammer mass weight is propelled by an elastomer band (i.e. a very large rubber band) onto an impact plate, producing an impact frequency range of 10-250Hz. The source is controlled with a hand held motor controller,  and can operate in single cycle or continuous cycle mode. The device is powered by a 12V large capacity battery (car battery).  The PEG-40Kg was received, assembled, and field-tested by  EPIC staff on June 23rd-28th, 2011.

PH5 Data Flow

PH5 data flow. The left column shows the general process one follows during the preparation of a PH5 data set.  The right side shows the various software tools and files necessary to complete the process.

Related categories:

Archival and Analysis Formats - All about PH5 and SEG-Y

  New to active source data archiving?

Here you will find information describing active source data formats: PH5, recommended for archiving data and SEG-Y, required by the user community for analysis and research.

 

Related categories:

PH5: What is it?

 

 

PH5 is the recommended archival format for active source data sets.  EPIC has transitioned from SEG-Y to PH5, EPIC's implementation of the hierarchical data format, version 5 (HDF5) data model, as the preferred archival format for active source data sets.  The strengths of HDF5 made it an attractive model for an active source archival data format.

HDF5:

Related categories:

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.

Related categories:

SEG-Y files produced from PH5 data sets

 

The SEG-Y file written by ph5toseg is in big endian byte order and attempts to follow the SEG-Y rev 1 standard (May 2002) as outlined in the table below.

The file does not contain a Tape Label.

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