EarthScope Data

USArray Data at the DMC

The USArray component of the EarthScope experiment is a continental-scale seismic observatory designed to provide a foundation for integrated studies of continental lithosphere and deep Earth structure over a wide range of scales. USArray will provide new insight and new data to address fundamental questions in earthquake physics, volcanic processes, core-mantle interactions, active deformation and tectonics, continental structure and evolution, geodynamics, and crustal fluids (magmatic, hydrothermal, and meteoric). Learn more »

Quick links:
Transportable Array Overview
Reference Network Overview
Flexible Array Overview
Magnetotelluric Overview
All USArray Stations
Quality Control
Data Access
Data Access Examples
DMC EarthScope stats

USArray Data Overview

The IRIS DMC is the final archive and distribution point for all raw USArray data from each sub-component: Transportable Array, Reference Network (Backbone/Permanent Array), Flexible Array and Magnetotelluric Array.

The DMC's Virtual Network concept can be used to select various components of USArray data. The following table illustrates the scope of the USArray virtual networks:

USArray Transportable Array

The Transportable Array is a set of 400 broadband stations that will, over the 10 year course of the project, traverse the conterminous United States. The DMC receives 40 and 1 samples/second seismic data streams from each site in addition to related state-of-health data in real-time.

Station lists:

Station maps:

Map Data	Description
Operating Stations Google Map	Operating TA stations as a web-viewable Goole Map
Operating Stations KML	Operating TA stations as a KML NetworkLink (e.g. for Google Earth)
Operating Stations GIF	Operating TA stations as a GIF image file
All Stations Google Map	All TA stations (past, present & future) as web-viewable Google Map)
All Stations KML	All TA stations as a KML NetworkLink (e.g. for Google Earth)

USArray Reference Network (including Backbone/Permanent Array)

The Reference Network is composed of permanent stations at a roughly 300 km spacing across the United States and includes the 39 EarthScope-funded Permanent Array stations. The DMC receives 40 and 1 samples/second seismic data streams from most sites.

Station lists:

Station maps:

Map Data	Description
Station Google Map	Permanent Array stations as web-viewable Google Map
Station KML	Reference Network stations as a KML NetworkLink (e.g. for Google Earth)
Station Map GIF	Reference Network stations as a GIF image file, conterminous US only

USArray Flexible Array

The Flexible Array is a set of broadband and active-source oriented instruments deployed on a temporary basis according to individual proposal (the PASSCAL model). Data rates and availability from Flexible Array deployments depend on the individual proposals.

Station lists:

Station maps:

Map Data	Description
Station Google Map	Flexible Array stations as web-viewable Google Map
Station KML	Flexible Array stations as a KML NetworkLink (e.g. for Google Earth)
Station Map GIF	Flexible Array stations as a GIF image file

USArray Magnetotelluric

The magnetotelluric (MT) component of USArray consists of 7 (when fully deployed) permanent MT stations and a mobile array of 20 MT stations that will each be deployed for a period of about one month in regions of identified interest with a spacing of approximately 70 km.

Station lists:

Station maps:

Map Data	Description
Station Google Map	Magnetotelluric stations as web-viewable Google Map
Station KML	Magnetotelluric stations as a KML NetworkLink (e.g. for Google Earth)
Station Map GIF	Magnetotelluric stations as a GIF image file

All USArray Stations

Station lists:

Station maps:

Map Data	Description
Operating Stations Google Map	Operating USArray stations as a web-viewable Goole Map
Operating Stations KML	Operating USArray stations as a KML NetworkLink (e.g. for Google Earth)
Operating Stations GIF	Operating USArray stations as a GIF image file, conterminous US only
All Stations Google Map	All USArray stations (past, present & future) as web-viewable Google Map)
All Stations KML	All USArray stations as a KML NetworkLink (e.g. for Google Earth)

USArray Quality Control at the DMC

The DMC performs both automated and manual quality control on USArray data. A small team of analysts review raw USArray data regularly in addition to performing higher level quality control measurements. More details are available on the USArray Quality Control Overview page.

To Request USArray Data from the DMC

All USArray data at the DMC is managed within the existing DMC infrastructure along with all the other, non-USArray data at the DMC. This means that USArray data is available via all the DMC's traditional request mechanisms.

Before requesting data for the first time, we recommend that you learn about requesting and using IRIS data by reading our IRIS DMC Data Access Tutorial.

Real-time data: IRIS distributes near-real time miniSEED data directly from our real-time collection system (BUD). Click here for details about getting data from our real-time systems. The recommended method for receiving real-time data feeds is with the DMC's SeedLink service.

Data from both the Transportable Array and Reference Network are delivered to the DMC in near-real time in SEED format. It is available via all the DMC's traditional request mechanisms including near-real time. Approximately 7 days after arriving at the DMC the data are copied to the primary archive making them available to all request mechanisms. The data remain in, and are available via, the real-time collection system (BUD) for two months.

Transportable Array SEED data qualities (in order of increasing preference):

Transportable Array data do not contain routine timing or other corrections, the differences in the data qualities is primarily completeness and, in the case of TA Final data sets, richness in terms of included data quality bits in the Mini-SEED headers.

Most DMC request mechanisms will default to returning the highest quality data, or a mix thereof, available for the request. Some request mechanisms also allow selection of specific qualities.

Flexible Array

Flexible Array experiments are usually conducted like traditional IRIS PASSCAL experiments in that data is retrieved from the field at specific intervals, sent to the PASSCAL Instrument Center and finally shipped to the DMC. These data are available via all the DMC's traditional request mechanisms shortly after being received at the DMC with the access method dependent on the data type (either the SEED archive or Assembled data sets).

In some cases Flexible Array experiment data are telemetered in near-real time to the DMC in which case the data is managed similarly to Transportable Array, Reference Network or other real-time data feeds.

There are a couple of options for a user to keep their metadata and response information up-to-date.

1) FetchResp - A DHI client
Available from the DMC's software list, the FetchResp program can be used to continuously check the DMC's metadata holdings for updated information and refresh a local copy of SEED RESP files.

2) RefreshMetaData.sh - Shell script
An example shell script is provided in the form of RefreshMetaData.sh which will, on demand check the DMC's FTP site for new network-oriented dataless SEED files and download them to refresh a local copy. The example script requires the 'wget' program. The script can easily be extended to process any newly arriving dataless SEED using, for example, rdseed to automatically refresh SEED RESP or SAC poles and zeros files.

There are other methods of automating the syncronization of metadata including the DHI-based SOD program described below.

USArray Data Access Examples

This section is not intended to be an exhaustive tutorial for DMC data access, that function is served by the IRIS DMC Data Access Tutorial. Instead the purpose of these examples are to provide a brief illustration of and kickstart for data access.

The preferred method to get continuous, real-time data feeds from USArray stations is to use the IRIS DMC's SeedLink service. Note that most but not all USArray stations are delivered to the DMC in real-time.

SeedLink client software exists for Antelope, Earthworm, SeisComP and a command line client, slarchive, that will write Mini-SEED data directly into the directories and files of your chosing. In the case of Antelope and Earthworm, client programs are included with the recent releases, otherwise source code for client software can be found on the SeedLink service overview page.

breq_fast is an email-based request mechanism. A user sends a formatted request to breq_fast at iris.washington.edu, after which the user is notified by email when the request is ready to download from the DMC. The breqfast format is described here.

As a simple example, requesting a 40-minute window of data from the LHZ channel of every TA network station could be done by sending the following in the body of an email to breq_fast at iris.washington.edu:

.NAME Joe Researcher .EMAIL joe@university.edu .MEDIA FTP .LABEL TA-TongaEvent .END * TA 2006 05 03 15 30 00.0 2006 05 03 16 10 00.0 1 LHZ

Note that this request only includes the "TA" network stations (the stations installed by IRIS specifially for the Transporable Array). To request data from all Transporable Array stations including the shared and cooperative stations replace the "TA" network code with the "_US-TA" virtual network code.

JWeed:

JWeed is a DHI client which incorporates many important request elements into a single application. JWeed's GUI allows a user to select stations and/or events using numerous criteria include arbitrary geographical areas. It would be straight forward, for example, to select events in a specified region and request event-windowed data for the USArray Reference Network stations. JWeed is available for download here and documentation is available here.

SOD:

SOD (Standing Order for Data) is a DHI client which is intended to automate data selection, downloading, and routine processing tasks. Numerous criteria are available for data selection, allowing much like JWeed, a user to request event-windowed data from the USArray Reference Network stations for events in a selected geographical region. Unlike JWeed, SOD, if configured and left running, will continue to download data that fits the criteria as events happen. SOD is available for download here and documentation is available here.

As a relatively simple example, the SOD "recipe" below will continue to run for the next 1000 years downloading event-windowed data for the "TA" network for every event of magnitude greater than 6.0.

<?xml version="1.0" encoding="UTF-8"?> <sod> <eventArm> <eventFinder> <name>IRIS_EventDC</name> <dns>edu/iris/dmc</dns> <originTimeRange> <startTime> <earlier> <timeInterval> <unit>DAY</unit> <value>1</value> </timeInterval> </earlier> </startTime> <endTime> <later> <timeInterval> <unit>GREGORIAN_YEAR</unit> <value>1000</value> </timeInterval> </later> </endTime> </originTimeRange> <magnitudeRange> <min>6.0</min> </magnitudeRange> <catalog>PREF</catalog> </eventFinder> <removeEventDuplicate/> </eventArm> <networkArm> <networkFinder> <name>IRIS_NetworkDC</name> <dns>edu/iris/dmc</dns> </networkFinder> <networkCode>TA</networkCode> <channelAND> <bandCode>B</bandCode> <gainCode>H</gainCode> </channelAND> </networkArm> <waveformVectorArm> <phaseRequest> <model>prem</model> <beginPhase>ttp</beginPhase> <beginOffset> <unit>SECOND</unit> <value>-120</value> </beginOffset> <endPhase>2.0kmps</endPhase> <endOffset> <unit>SECOND</unit> <value>60</value> </endOffset> </phaseRequest> <fixedDataCenter> <name>IRIS_BudDataCenter</name> <dns>edu/iris/dmc</dns> </fixedDataCenter> <someCoverage/> <mseedWriter/> </waveformVectorArm> </sod>

Several more SOD recipes are available in the online SOD documentation.