Open Data Exchange in Support of CTBT ResearchDavid Simpson and Raymond Willemann, IRIS Consortium
Collecting Open DataMany geophysical data collection systems are comprised of tens or hundreds of technologically advanced instruments, installed to exacting standards. The instruments are dispersed to widely distributed sites, often far from support facilities, and yet must be well maintained in order to collect data that satisfy many missions. Such systems are expensive both to build and operate – so many of their owners are inclined either to keep the data to themselves or attempt to recoup costs. Often, data are made openly available only if the operator has, a priori, a strong ethos of openness or if an outside community or funding organization compels it.
Global Seismographic Network – GSNIRIS, in collaboration with the U.S. Geological Survey, built and manages operation of the GSN, with an explicit commitment of making the data openly available. Data from almost all GSN stations are available in near-real-time, and IRIS assists other organizations in establishing robust parallel telemetry for mission-critical operations.
Program for Array Seismic Studies of the Continental Lithosphere – PASSCALIRIS built and manages a pool of portable instruments and provides services for their use in temporary deployments around the world. Priority of use is extended to deployments funded by the US government, but the only absolute requirement is that investigators must give a copy of the data to IRIS, which will make them openly available. IRIS helps investigators to upload data from the field instruments, to organize auxiliary information into well-formatted metadata, and to organize the data for reliable, long-term archiving and easy re-use.
U.S.G.S. Advanced National Seismic System – ANSSAs part of its monitoring activities, the ANSS includes a national Backbone network and 15 regional seismic networks operated by U.S. Geological Survey and its partners. Avoiding restrictions on the data makes it easier for the USGS to provide real-time earthquake information for emergency response personnel, provide engineers with information about building and site response to strong shaking, and provide scientists with high-quality data – for example by allowing others, including IRIS, to re-distribute ANSS data.
Managing Open DataHistorically, many types of geophysical data have been lost, or become difficult, when investigators with tacit knowledge move on, when technology changes, or when recording media deteriorate. Managing data for long-term use by many users begins with an initial investment at the time of collection to ensure data quality, to record auxiliary information as documented metadata, and to adhere to widely-used standards for data format. Ongoing investment is required to maintain the integrity of the data and to ensure that they remain accessible as user practice evolves.
Data Management System – DMSIRIS built and operates a Data Management Center (DMC) and coordinates operation of GSN Data Collection Centers (DCC). Collectively, these facilities implement quality control procedures that include compiling statistical indicators of data quality, intervening to diagnose and possibly repair problems when there are statistical outliers, and replacing data that were degraded by the original telemetry. The DMC routinely updates its IT hardware and transcribes its complete data holdings to new media, and maintains multiple back-up copies, of which some are off-site.
International Federation of Digital Seismographic Networks – FDSNCoordination among experts and users in many countries is essential for collecting a managing global geophysical datasets. Among seismological data organizations, the FDSN has served as a forum for coordination for nearly 25 years. Among other activities, the FDSN has developed worldwide standards for documenting, storing and exchanging seismological data, helped member networks to establish complementary station locations, and documented station information in its Station Book.
Data AccessTo make data truly open, data managers must implement data discovery and access tools, reach out to users to learn about their needs, and make ongoing investments in improving and adapting the tools to the evolving needs of users. Users require a range of access tools for different purposes, which might be related to selected events in the past, related events meeting particular criteria, or for data without any simple relationship to events. Different users will require access through e-mail, web browsers, or interfaces that can be accessed by the users own programs.
Benefits from Open DataIn the long run, the owners of geophysical data benefit from making them openly available. This is especially true when the governing body and the funding agencies acknowledge the benefits.
Data UsageWith a few partial exceptions, such as petroleum companies and weather forecasters, most users of geophysical data are not engaged in commercial activities. Since non-commercial users rarely can secure funding to purchase access to data that have already been collected, freely and openly distributed data are much more widely used.
Data QualityWide usage means much more frequent, rigorous, and innovative checks on data quality. Many users will interactively review the data, and may spot anomalies in the data that are not captured by statistical indicators already in use
CTBT Operations and ResearchMany GSN stations are used as IMS Auxiliary seismic stations. Data archived at the IRIS DMC from the GSN, PASSCAL and other sources are used in research to improve event characterization and models of travel time and attenuation. At recent “Monitoring Research Reviews” papers based on IRIS-derived data have included results for Korea, the Middle East, Africa, Central Asia, and the Caucasus.
IRIS / IDA Stations IRIS / USGS Stations Affiliate StationsPlanned Stations
SLBS
MACI
KNTN
WANT
UOSS
COR
TARA
CMBPASC
PFO TUC
RSSD
FFC
COLA
KDAK
ANMOHKT
CCM
TEIGSJG
DWPFBBSR
WCI
WVTSSPA
KIP
POHAJOHN
XMAS
RARPTCN RPN
MSEY
DGAR
PALK
CHTO
TATO
MIDWMAJO
PET
BILLTIXI YAK MA2
TLY
ULN
LSA
HIA
BJTXAN SSE
MDJ
KMI
INCN
YSSERM
ENH
COCO
SBA
CTAORAO
HNR
BTDF
KAPI
MSVF
GUMO
WAKE
KWAJ
FUNA
AFI
DAV
QSPA
CASY
SURLBTB
LSZ
MSKU
FURI
MBAR
KMBO
NWAOTAU
WRAB
SNZO
EFI
PMSA
HOPE
ASCN
SHEL
TRQALCO
NNA
PAYGOTAV
PTGA
JTSSDV
LVC
SAML
SACV
CMLAHRV PAB
SFJD BORG
ESK
TRIS
RCBR
TSUM
KOWA
ALEKBS
NRIL
ARU
BRVKKURK
MAKZ
WMQNIL
RAYN
ABKT
LVZ
OBN
KEVKONO
KIEVBFO
GRFO
GNIANTO
AAK
PMG
KIV
QIZ
MBWA
ILAR
PDARNVAR
ADK
ATTU
VNDA
s
TXAR
SDDRBCIPTGUH BBGH
GRGR
ANWBGTBY
ABPO
MCQ
KBL
GRTKMDTJ
IRIS DMC Archive GrowthSingle Sort
May 1, 2009
0
10
20
30
40
50
60
70
80
90
100
Jan-9
2
Jan-9
3
Jan-9
4
Jan-9
5
Jan-9
6
Jan-9
7
Jan-9
8
Jan-9
9
Jan-0
0
Jan-0
1
Jan-0
2
Jan-0
3
Jan-0
4
Jan-0
5
Jan-0
6
Jan-0
7
Jan-0
8
Jan-0
9
Date
Arch
ive S
ize (
terab
yte
s)
EarthScope
PASSCAL
Engineering
US Regional
Other
JSP
FDSN
GSN
IRIS DMC Archive GrowthSingle Sort
May 1, 2009
0
10
20
30
40
50
60
70
80
90
100
Jan-9
2
Jan-9
3
Jan-9
4
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1
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2
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6
Jan-0
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Jan-0
8
Jan-0
9
Date
Arch
ive S
ize (
terab
yte
s)
EarthScope
PASSCAL
Engineering
US Regional
Other
JSP
FDSN
GSN
U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
ANSS BACKBONE NATIONAL NETWORK
BMN
PAS
CMB
WVT
WCI
TUC
HRV
HKT
COR
CCM
PFO
BLA
SRU
DUGWCN
AAMWDC
SAO
JCT
MSOLA0
BOZ
PAL
ISA
OXF
NEW
CBN
SSPA
RSSD
DWPF
ANMO
CCUT
HUMO
NATXMNTX
KVTX
AMTX
ERPA
ACSO
EGMT DGMT
RLMT LONY
KSU1
VBMS
TZTN
SWET
LRAL
BRAL
WVOR
WUAZ
WMOK
TPNVSDCO
SCIA
PKME
OGNE
MVCO
NLWA
NHSCMIAR
MCWV
LBNH
JFWS
ISCO
HLID
HDIL
HAWA
GLMI
GOGA
EYMN
ECSD
COWI
CNNC
CBKS
BMOR
BINY
AGMN
PINOR
TXAR, LTX
NVAR, MNV
PDAR, BW06
MCCM
120°125°
115°
115°
110°
110°
105°
105°
100°
100° 95°
95°
90°
90°
85°
85°
80°
80°
75°
75°
70° 65°
25° 25°
30° 30°
35° 35°
40° 40°
45° 45°
ADK
PMR
TNA
BMR
SMY
SDN
COLA
KDAK
WRAK
EGAK
170°
180°
180°
170°
170°
160°
160° 150°
150°
140°
140°
130°
50°
60°
60°
KIP
POHA160° 155°
20°
Background:Peak ground acceleration having a 2% probability ofexceedance in 50 years. For more information, seehttp://earthquake.usgs.gov/research/hazmaps/
Station LegendANSS Backbone stations operated by USGS
USArray stations upgraded by Earthscope for NSF, operated by USGS
USArray stations contributed by Earthscope for NSF, operated by USGS
Global Seismographic Network stations, operated by USGS and IRIS
Stations operated by ANSS partners, data contributed to USGS
Status February 2007
version 3/15/2007 5 pm
JapanIRIS GSN U.S.Australia Germany ItalyFrance OtherCanada
International Federation ofDigital Seismograph Networks
6/2008
SEEDReference Manual
Standard for the Exchange of Earthquake Data
International Federation of Digital Seismograph NetworksIncorporated Research Institutions for Seismology
United States Geological Survey
SEED Format Version 2.4January, 2009
JapanIRIS GSN U.S.Australia Germany ItalyFrance OtherCanada
International Federation ofDigital Seismograph Networks
6/2008
Figure 8. Left: Event 2000256 (9/12/2000, Mw6.1), 2003107 (4/17/2003, Mw6.3) and IRIS station distributions.
Source 2000256 (9/12/2000, Mw6.1) is used to obtain the velocity structures. Right: Best P-wave and S-wave velocity structures for the paths between event 2000256 and IRIS stations obtained from 1D forward modeling.
Figure 9: Top: Moment tensor solution for event 2003107 in the 0.005-0.03Hz range using Green’s function
which were computed from the velocity model obtained using the 2000256 event (Figure 9). Bottom: Global CMT solution from Harvard University.
Figure 10 shows another example, providing coverage of the region from the oceanic side. We note the significant lateral variations in S velocity in the top layer.
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