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

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

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.

2008 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

248