CORS911: REAL-TIME SUBSIDENCE MONITORING OF THE NAPOLEONVILLE SALT DOME SINKHOLE USING GPS

CORS911: REAL-TIME SUBSIDENCE MONITORING OF THE NAPOLEONVILLE SALT DOME SINKHOLE USING GPS LSU Center for GeoInformatics Joshua D. Kent & Larry E. Dunaway 29 th Annual Louisiana Remote Sensing & GIS Workshop Lafayette, LA April, 24, 2013

1. The Situation 2. A Timeline PRESENTATION OVERIVEW 3. Nature of the Sinkhole 4. Efforts by the C4G 5. Current Status 6. Long-term Plans August 9, 2012 7. Conclusion March 23, 2013 4/30/2013 LSU Center for GeoInformatics 2

Bayou Corne ESRI Imagery (2013) 4/30/2013 LSU Center for GeoInformatics 3

Bayou Corne LiDAR from LOSCO (2002) 4/30/2013 LSU Center for GeoInformatics 4

Bayou Corne Salt dome contours by New Orleans Geological Society (1965) 4/30/2013 LSU Center for GeoInformatics 5

Bayou Corne Sinkhole Data from LADNR (2013) 4/30/2013 LSU Center for GeoInformatics 6

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Approx. Sinkhole Location & Depth Model of Unstable Zone OXY #1 OXY#3: Well to the collapsed brine cavern OXY #3 OXY #2 OXY #9

TIMELINE & INFORMATION RESOURCES 4/30/2013 LSU Center for GeoInformatics 9 http://www.assumptionla.com/bayoucorne

(March 2013) CURRENT SITUATION Sinkhole area is ~12 acres and ~200 deep. Subsidence zone is ~20 acres. Cavern Breach is approx. 1 mile beneath surface 45 million cubic ft. of natural gas seeping up to the water table. 19 wells venting natural gas from beneath the aquifer. Cavern still unstable. Various monitoring strategies in place and planned. Flare Stack north of Hwy70 4/30/2013 LSU Center for GeoInformatics 10

Oxy Geismar Well No. 3 Timeline BRIEF TIMELINE April 1982: Oxy Geismar Well No. 3 permitted for mining salt water brine. 1995: Texas brine received permission from Louisiana Department of Natural Resources to store Naturally Occurring Radioactive Material (NORM) in the well. May 2010: DNR issues permit to mine a section of salt above the existing cavern roof (3,400 feet deep). June 2011: Texas Brine notifies DNR that integrity of the well had been lost. Wellbore above the cavern was plugged with cement. 4/30/2013 LSU Center for GeoInformatics 11

Oxy Geismar Well No. 3 Timeline BRIEF TIMELINE 31 May 2012: parish officials were notified of areas of bubbling spots in the Bayou Corne and Grand Bayou waterways. 19 June 2012: Parish Emergency Declared. 3 Aug. 2012: 372 diameter sinkhole forms overnight. State Emergency Declared. 3 Aug. 2012: Mandatory Evacuation Ordered for >150 Residents. 20 Dec. 2012: Sinkhole expands to 8.4 acres. Gas venting underway. 19 March 2013: Gov. Jindal visits sinkhole. 5 April 2013: Blue Ribbon Commission convenes to provide science-based recommendations for public safety. 4/30/2013 LSU Center for GeoInformatics 12

Salt Domes for the Northern Gulf of Mexico Amoco Production Company (Lopez & Orgeron, 1995) The Napoleonville Saltdome: NOGS (1995), and attribution LGS (2002) 4/30/2013 LSU Center for GeoInformatics 13

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Approximate Location of Cavern 4/30/2013 LSU Center for GeoInformatics 17

Sinkhole Data from LADNR (2013) 4/30/2013 LSU Center for GeoInformatics 18

Sinkhole Data from LADNR (2013) 4/30/2013 LSU Center for GeoInformatics 19

Approximate Location of Cavern 4/30/2013 LSU Center for GeoInformatics 20

Approx. area of instability QUATERNERY Holocene Pleistocene NEOGENE Pliocene Miocene Depth:5,654ft 4/30/2013 LSU Center for GeoInformatics 25

C4G RESEARCH GRANTS LA Transportation Research Center Awards Two Grants to the Center for GeoInformatics to Monitor and Assess the Stability of Highway 70 September 2012: C4G to Measure the Horizontal and Vertical Positions of Control Points Along Highway 70 April 2013: C4G to Install and Maintain Five GPS Monitoring Stations to Measure Positions 24-7-365 4/30/2013 LSU Center for GeoInformatics 26

Workflow Consisting of 3 Tasks Executed Over 9 Months: CONTROL POINT PROJECT TASKS 1. Collect and measure horizontal and vertical positions at select control points located along Highway 70 in Assumption Parish. 2. Process the data for use in a GIS. 3. Distribute the data via FTP. 4/30/2013 LSU Center for GeoInformatics 27

PROJECT AREA: Assumption Parish, Louisiana LA Highway 70 District 61 Control Section: 232-01

METHODOLOGY Capture Point Measurements Along Highway 70 Using GPS: Points on Hwy 70 along north shoulder Points on bridges at Grand Bayou and Bayou Corne GPS measurements captured via 5-minute occupations (300 epochs) Enhanced using C4Gnet Real- Time Network Horizontal: ~10-mm (0.39 inches) Vertical: ~20-mm (0.79 inches) 4/30/2013 LSU Center for GeoInformatics 29

Time Period of Observations: WORK SCHEDULE Biweekly Observations: 9/12 10/12 Weekly Observations: 11/12 12/12 Monthly Observations: 01/13 06/13 4/30/2013 LSU Center for GeoInformatics 30

Size of the points are proportional to the variance of the measurements over time.

METHODOLOGICAL LIMITATIONS Sporadic vs. Long Term Occupation Individual measurements exhibit both random and systematic error. Random Error: Caused by unknown and unpredictable changes in environmental conditions: Atmospheric conditions Environmental Disruptions (wind, aerodynamic drag, etc.) Micro-variations in satellite orbits Systematic Error: Caused by predictable changes in environmental conditions and procedures: User & instrument error Signal multipath & tree canopy Tidal effects on the landscape Poor satellite geometry EM interference from nearby transmitters 4/30/2013 LSU Center for GeoInformatics 35

METHODOLOGICAL LIMITATIONS Sporadic vs. Long Term Occupation Long-term measurements are less susceptible to both random and systematic error. Random Error: Reduced by long-term occupations. Provides more precise measurements of surface conditions. Systematic Error: Constrained when following best practices. Predictable environmental conditions can be removed using data models. Mitigates predictable errors to provide more accurate measurements of surface conditions. 4/30/2013 LSU Center for GeoInformatics 36

INTRODUCING CORS 911 LTRC Awards a Grant to C4G to Install Five (5) Continuously Operating GPS Reference Stations (CORS) CORS911: Continuously Operating Reference Stations for the Bayou Corne Sinkhole Monitor horizontal and vertical positions 24-7-365 Quantify differential and network motion. 4/30/2013 LSU Center for GeoInformatics 37

Workflow Consisting of 7 Tasks Executed Over 12 Months: PROJECT TASKS 1. Perform Site Assessments 2. Custom CORS Fabrication 3. Deploy CORS 4. Monitoring Implementation 5. Utilization & Client Support 6. Maintenance 7. Reporting 4/30/2013 LSU Center for GeoInformatics 38

PROJECT AREA: Assumption Parish, Louisiana LA Highway 70 District 61 Control Section: 232-01 Pending Right of Way Access

BENEFITS OF A CORS NETWORK Improve Monitoring of Highway Stability using CORS Technology Software to Monitor the Locations of Individual CORS sites Relative to the Continent and to Each Other Coordinate Monitoring: real-time measurements relative to the North American continent. Rapid Motion Detection: measure rapid changes of an antenna s position. Differential Motion Detection: monitor short and long-term positional changes relative to a fixed location. Network Motion Detection: track the long-term changes to basic positional geometry of the CORS sites relative to a fixed external network location. Data Storage Integrity: local storage for fault tolerant recording of telemetry in the event of communication outages. Real-time and Web-based Monitoring with user configured notification and alarms. 4/30/2013 LSU Center for GeoInformatics 40

Establishing a CORS911 Site: METHODOLOGY Add CORS to the RTN CORS positions to cook-down for ~3-Days Adjust positions to match Network Solution relative to Oakdale, LA Validate positions with OPUS Monitor position integrity: Coordinate Monitoring Network Motion Differential Motions Rapid Motion 4/30/2013 LSU Center for GeoInformatics 41

CORS1 Bayou Corne

CORS1 Bayou Corne

CORS3 Grand Bayou

CORS3 Grand Bayou

CORS4 Bayou Choupique 4/30/2013 LSU Center for GeoInformatics 48

CORS4 Bayou Choupique 4/30/2013 LSU Center for GeoInformatics 49

DETECTING MOTION C4GNet RTN Uses Integrity Monitoring Algorithms to Detect Motions Set integrity monitoring relative to other CORS within the network Anchor to a single location Anchor to multiple locations Use floating reference sites to aid interpretation 4/30/2013 LSU Center for GeoInformatics 51

Synchronizing CORS911 Relative to the C4GNet RTN Network Motions Relative To The Fixed Point At Oakdale, LA Other CORS Sites Used As Reference 4/30/2013 LSU Center for GeoInformatics 52

Synchronizing CORS911 Relative to the C4GNet RTN Other CORS Sites Used As Reference Network Motions Relative To Multiple Fixed Points Network Motions Relative To Multiple Fixed Points 4/30/2013 LSU Center for GeoInformatics 53

Synchronizing CORS911 Relative to the C4GNet RTN 54

IMPLEMENTING AN ALERT SYTEM Monitoring & Alert System To support decision support, the Integrity Monitoring System will Issue Daily Reports and Email Alerts Daily Reports: Monitor the positions of each CORS site relative to the Oakdale, LA, reference station Email Alerts: Establishes thresholds that, if crossed, will trigger an alert: WATCH ALERT: threshold is briefly violated. WARNING ALERT: threshold is violated for an extended period of time. Assessments: Develop a method for the interpreting the Alert 4/30/2013 LSU Center for GeoInformatics 55

INTEGRITY MONITORING Generate Reports EXAMPLE: 4/30/2013 LSU Center for GeoInformatics 56

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Simplified Reporting via Secure Web Site 4/30/2013 LSU Center for GeoInformatics 60

Displacement in Northing: EXAMPLE 1.5 mm (0.059 ) Displacement [m] 4/30/2013 LSU Center for GeoInformatics 61

Displacement in Easting: EXAMPLE 1.4 mm (0.055 ) Displacement [m] 4/30/2013 LSU Center for GeoInformatics 62

Displacement in Vertical: EXAMPLE 2.1 mm (0.083 ) Displacement [m] 4/30/2013 LSU Center for GeoInformatics 63

Scatter Plots: EXAMPLE 1.5 mm (0.059 ) 4/30/2013 LSU Center for GeoInformatics 64

Sinkhole in the Napoleonville Salt Dome: CONCLUSIONS Oxy #3 cavern breached the Western wall of the salt dome. Unstable material shifted, causing sinkhole to form in the alluvium. Modeled output will be used to develop a long-term strategies for monitoring in the area. 4/30/2013 LSU Center for GeoInformatics 65

Two Advanced Geodetic Monitoring CONCLUSIONS Solutions Implemented by the C4G Static measurement of horizontal and vertical positions at control points along Hwy 70 Continuous measurement of positions using CORS 911 stations installed along Hwy 70 4/30/2013 LSU Center for GeoInformatics 66

CONCLUSIONS The Findings So Far No discernible movement of Hwy 70 relative to the sinkhole. Ad hoc GPS readings exhibit variability associated with random and systematic error. Long-term occupation using CORS technology was initiated to assess differential motions to provide more reliable measurements. CORS technologies provides a comprehensive solution with direct access to telemetry in real-time. 4/30/2013 LSU Center for GeoInformatics 67

QUESTIONS & CONTACT INFO Questions? Joshua D. Kent, Ph.D. Center for GeoInformatics Louisiana State University Baton Rouge, LA 70803 http://c4g.lsu.edu 4/30/2013 LSU Center for GeoInformatics 68