1 / 28

Guoquan (Bob) Wang University of Houston

Current Land Subsidence in the Houston Metropolitan Area, Texas, Derived from GPS Observations (1993-2012). Guoquan (Bob) Wang University of Houston. With contributions from graduate students: Timothy J. Kearns, Jiangbo Yu, Linqiang Yang, Xueyi Jia, and Jianjun Jiang. Outline.

kert
Download Presentation

Guoquan (Bob) Wang University of Houston

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Current Land Subsidence in the Houston Metropolitan Area, Texas, Derived from GPS Observations (1993-2012) Guoquan (Bob) Wang University of Houston With contributions from graduate students: Timothy J. Kearns, Jiangbo Yu, Linqiang Yang, Xueyi Jia, and Jianjun Jiang

  2. Outline • GPS Geodesy Infrastructure in the Houston area Public available GPS stations (Hardware) Stable Houston Reference Frame (SHRF) (Firmware) Single-receiver phase ambiguity resolved GIPSY PPP resolution (software) • Current subsidence mapping (2005-2012) • Scientific Questions: (1) Is there deep seated (or fault-controlled) subsidence in the Houston area? (2) When will the current subsidence stop?

  3. Historic Subsidence in Houston 3 m within 30 years, 10 cm/year (USGS, Coplin and Galloway, 2009) (USGS, Kasmarek et al., 2009) 6 m USGS

  4. Houston Ship Channel Area

  5. Geodesy Infrastructure: Permanent GPS Stations Harris-Galveston Subsidence District (70+) Texas Department of Transportation 15+ 83 GPS +11 Extensometers City of Houston, others

  6. HoustonNet • NSF MRI: 40 GPS; UH: 10 GPS • Subsidence, faulting, and salt dome uplift • Hurricane intensity forecasting • Civil engineering community---buildings, bridges, dams, sea walls

  7. Geodesy Infrastructure: The Stable Houston Reference Frame Helmert Transformation 7 years: 2005-2012 Wang et al., 2013

  8. 14-Parameter Similarity Transformation • Translation along the respective axis (in meters) • Differential Scaling of the respective axis (ppb) • Counterclockwise Rotations (in radians)

  9. 14-Transformation Parameters NGS *Pearson and Snay (2013), Table 7

  10. No-linear subsidence rate 18 Years Jersey Village Spatial and temporal variation of subsidence

  11. Ground Deformation at Closely-Spaced (4 km) GPS Sites

  12. Recent Subsidence Mapping (2005-2012) 85 years 6 m 83 GPS +11 Extensometers

  13. Maximum subsidence rate <=2.5 cm/year < 5 mm/year 7 years: 2005-2012

  14. Aquifer Profile: Chicot + Evangeline 3600 ft USGS

  15. Question 1: Is there deep-seated (fault-controlled) subsidence in the Houston-Galveston area? Gulf Coast Geology and faults Subsidence---pumping (??%)+ faulting (??%) Subsidence vs. Faulting Ortega, 2013

  16. USGS Borehole Extensometers Compaction meter USGS 13 extensometers at 11 sites 40 years: 1974—2013

  17. Addicks Borehole Extensometer (-549 m)

  18. Co-Located GPS and Extensometer Monitoring Site (ADKS) +15 years Wang et al., 2014

  19. 18 years Wang et al., 2014 Journal of Surveying Engineering 40 years Drought of 2011 Drought of 2005 Conclusion: The compaction measurements from the long-term extensometers are reliable and the accuracy is about a few millimeters.

  20. Co-located GPS and Extensometer Sites ADKS(-549 m) NETP (-591 m) LKHU (-661 m) 22 years Conclusion: Compacted aquifers are limited to above -600 m

  21. Clear Lake—Jonson Space Center Sites Clear lake Deep Borehole (-936 m) Clear lake Shallow Borehole (-530 m) Jonson Space Center(-235 m) 50m 2.5 km 37 years Conclusion: No compaction below -530 m

  22. -530 m USGS, 2009 Conclusion: Only partial of the Evangeline aquifer had been compacted!

  23. Coastal Subsidence: Galveston vs. New Orleans 4 mm/year It appears no considerable tectonic subsidence occurs currently in the Houston-Galveston area.

  24. UH Coastal Center “Vertical” GPS Array -1 ft -30 ft -10 ft -20 ft Borehole GPS

  25. Question 2: When will the subsidence cease? 1978-1998 38 years Conclusion: It took 20 years (1978-1998) to halt the subsidence in the southeast part.

  26. 38 years Conclusion: 2005+20=2025

  27. Summary • The ground water and aquifer systems respond slowly to human actions. It took almost two decades (1980s and 1990s) to halt the subsidence in the south-east part of the Houston metropolitan area. Therefore, a long-term perspective is needed to manage groundwater resources and control land subsidence. • The spatial and temporal variation of subsidence could be very considerable! subsidence=f(x,y,z t) • The groundwater regulations implemented by the HGSD are very successful in reducing subsidence rate in the Houston area.Currently, there is no considerable deep-seated or fault-controlled subsidencein the Houston-Galveston area. Current aquifer compaction is limited to about -530m. Thank you!

  28. Stable: v=0

More Related