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Facilitator: Dr Alexandros Savvaidis
TexNet and CISR initiatives to improve public safety
Alexandros Savvaidis, PI Seismology and TexNet Manager
TexNetUsing a 42-station backbone seismic network augmented by 40 temporary stations and local dense networks, TexNet is monitoring, locating, and cataloging earthquakes across Texas; disseminating earthquake data; and conducting research to improve our understanding of earthquake causes that can be used to improve practices and mitigate the hazard.
Center for Integrated Seismicity ResearchIndustry partnership leverages and extends TexNet earthquake monitoring and research to more thoroughly study earthquake occurrences, trends, and causes to develop effective mitigation strategies.
Texas Bureau of Economic Geology TexNet-CISR Program
TexNet deployment and operation
TexNet research
CISR IA research
35%
33%
32%
2015-2018
TexNet-CISR Timeline June 2015–July 2018
Original TexNet Legislation and
Funding
2015 2016 2017
First TexNet Station
Installed
TexNet Permanent
Network Finished
TexNet Earthquake
Catalog Public
CISR Launched
TexNet Raw Data Begins Streaming
2018
1st RISC Webinar
RISC* Formed
RISC: Regional Induced Seismicity Collaborative
TexNet-CISR Organization
Seismic Hazard and Risk Assessment
Geologic Characterization
UT Bureau of Economic GeologyUT Institute for GeophysicsUT Petroleum Geosystems and EngineeringUT Civil, Arch, and Environmental EngineeringUT Aerospace EngineeringTexas A&M Petroleum EngineeringSMU GeosciencesUniversity of Houston SeismologyUniversity of Texas at Dallas SeismologyUniversity of Texas at El Paso SeismologyStanford UniversitySouthwest Research InstituteGolder Associates
TexNet-CISR Program LeadershipPeter Hennings, PI Subsurface Integration and Industry Liaison
Ellen Rathje, PI Earthquake Hazard and RiskAlexandros Savvaidis, PI Seismology and TexNet Manager
Geomechanics and Reservoir ModelingSeismologyTexNet Seismic
NetworkSurface Deformation
and Geodetics
Scientific Themes
Collaborating Organizations Accountability and Feedback
Technical Advisory Committee – designated by Governor of Texas, multiple stakeholder groups (industry, academic, and public)
Science Advisory Committee – one representative from each CISR member
USGS authoritative network designation
Ad hoc committees for peer review
- funded by NASA- induced seismicity application only
Integrated Analyses: What’s Available Now and Near Future
• Earthquake analysis• Production/disposal fluid data
Earthquake characterizationInjection data and analytics
Static geologic characterization and earthquake analysisDynamic modeling and earthquake analysis
*
*
Study Areas
• Detailed earthquake catalog• Earthquake analysis• Production/disposal fluid data• New fault interpretation• Integrated geological model• Updated stress analysis• Fault slip potential• Spatiotemporal statistics• Pore pressure model
• Improved earthquake catalog• Production/disposal fluid data
• Detailed earthquake catalog• Production/disposal fluid data
• Detailed earthquake catalog• Double difference catalogs• Production/disposal fluid data• Delaware Mtn Gp. geomodel• DMG pore pressure model• New fault model
TexNet Network and Earthquake Catalog
42 Station Backbone for Texas
33 Portable Stations• 15 deployed in the DFW area• 7 deployed in the Snyder area• 8 deployed in Permian Basin area• 3 deployed in the Eagle Ford area
3 Stations deployed in NM (CISR)
4 Portable stations available• 1 to be deployed (Permian, Eagle Ford)• 3 available for immediate response
Dense local networks operated by• SMU: Fort Worth Basin• UTEP: Delaware Basin (2018)
Dense local networks to be deployed by• BEG-UTIG: Eagle Ford Operating Area
(2019)• BEG-UH: Midland Basin (2018)
Products of TexNet – CISR to support infrastructure issues
Seismicity Monitoring and Cataloging
Peak Ground Velocity (PGV) and Peak Ground Acceleration (PGA) for Texas
Local Ground Motion Prediction Equations (GMPE)
Vs30 map of Texas
Site amplification due to loose materials
Input motion for infrastructure design (observed response spectra)
Hazard and Risk Assessment
Shakemaps and Information Dissemination
TexNet Network and Earthquake Catalog
http://www.beg.utexas.edu/texnet/catalog
N = 3844
n = 126
[0-0.5] (0.5-1] (1-1.5] (1.5-2] (2-2.5] (2.5-3] (3-3.5] (3.5-4]
6
Earthquake Locations Using the 3D West TX/SE NM Model
Highlighting 4 earthquake clusters in the Delaware Basin• South (red)• Southeast (magenta)• Central (amber)• Southwest (blue)
Green dots are disposal wells(size = total disposed volume)
Faults are from the Tectonic Map of Texas (1997) and updated info
Grey layer is the top of Precambrian basement
Snyder• 11 earthquakes in 2 groups:
Distant:
• Epicentral distances ~ 300 km
• ML ~ 2.9 - 3.1
Near:
• Epicentral distances ~ 1-13 km
• ML ~ 2.7 – 3.1
Site amplification
• Calculation of H/V spectral ratio of earthquake data for s-wave energy
• Earthquake durations vary 15–120 seconds, time windows vary 5-10 seconds with 20% overlap
• H/V for ambient noise calculated from (4) 24 hour periods, using time windows of 120 seconds with 20% overlap
• Smoothing using Konno & Ohmachi smoothing window (b = 20)
Earthquake
Ambient Noise
Data and Processing
Snyder
• Station SN01 Interbedded silisiclasticformations with limestone
Snyder
• Most SN stations show peaks ~ 2-2.5 Hz and 5-8 Hz
• Some higher frequency peaks possible, but low amplitudes make them difficult to distinguish
Snyder
• Comparison of HVSR for TexNet stations with passive array HVSR: 60 m L-array deployed for 30 minutes
• Comparison to theoretical transfer functions for inversion of fundamental mode Rayleigh waves and fundamental mode Love waves.
• Lower cutoff frequency for theoretical transfer function ~7Hz, so lower frequencies are not resolved
Theoretical transfer functions and temporary array HVSR results provided by Yust, M. B. S. (2018) and Yust, M.B., Cox, B.R., Cheng, T. (2018)
Communicating with State Agencies & Local Authorities
Texas Division of Emergency Management• Created communications plan to inform TDEM of seismic events; info transmitted to local officials• Presented TexNet during TDEM emergency response conference• Organizing training webinar for regional coordinators
Railroad Commission of Texas• Maintaining ongoing technical discussions (every other month) with Oil and Gas Division personnel• Discussions of our understanding of subsurface conditions, when possible• Frequent discussions between State Seismology and TexNet personnel
Local Authorities• Reviewed communication plan with City of Irving authorities (fire, police, 911 coordinators, etc.), for events
>ML4.0. Coordinating other meetings with TDEM• Planning upcoming meeting in Irving in September• Presented to Pecos City Council
Collaboration with USACE
Regional Induced Seismicity Collaborative (RISC)
Entities Involved:• State geological surveys from TX, OK, KS, NM, AR• US DOE, Office of Fossil Energy• Groundwater Protection Council
Specific Goals:• Integrate approaches across States for geological interpretations and analyses• Improve management of produced water• Address other geological issues that could benefit from multi-state collaboration
Approach:• Develop a scientific, theme-based framework for collaboration• Organize webinars, targeted scientific meetings, and yearly all-hands technical meetings• Provide efficient pathways for data and information exchange
Status:• Funding is through DOE/NETL and administered by Groundwater Protection Council • Officially began early 2018
