LLNL Coal-Mining Seismicity Report

Seismic Characterization of Coal-Mining Seismicity in Utah for CTBT Monitoring

TABLE OF CONTENTS

TITLE PAGE

DISCLAIMER

EXECUTIVE SUMMARY

ACKNOWLEDGMENTS

1. INTRODUCTION

2. BROADBAND DIGITAL SEISMIC STATION (SRU)

3. MINING SEISMICITY AND AGROUND TRUTH - AN UPDATE

4. MECHANISMS OF SIGNIFICANT SEISMIC EVENTS

5. REFERENCES

LIST OF TABLES

Table 2-1

Hardware and Calibration Information for Station SRU

Table 3-1

Correction Terms Used by Arabasz et al. (1997) for Revised Coda Magnitudes, MC´, in the Wasatch Plateau-Book Cliffs Area

Table 3-2

Correction Terms Used in This Report, Following Arabasz and Wyss (1999), for Revised Coda Magnitudes, MC´, in the Wasatch Plateau-Book Cliffs Area

Table 3-3

Seismic Events of Magnitude 3.0 or Greater in the WP-BC Coal-Mining Area, January 1978-June 2000, Ranked by Size

Table 3-4

Information for Sample Areas in Figure 3-15 Used to Investigate the Association of Seismicity with Mining in the WP-BC Area During the Period 1992-2000

Table 4-1

Focal-Mechanism and Summary Information for Seismic Events of Magnitude 3.0 or Larger in the WP-BC Coal-Mining Area, January 1978-June 2000, Ranked by Size

Table 4-2

The Willow Creek Composite Velocity Model

Table 4-3

The Trail Mountain Composite Velocity Model

Table 4-4

Data for Seismic Events in Table 4-1 Having Only Dilatational P-Wave First Motions

Table 4-5

Location and Focal Mechanism Information for Seismic Events of Magnitude 3.0 or Larger in the Trona-Mining District of Southwestern Wyoming, January - August 2000

LIST OF FIGURES

Figure 1-1

Seismicity map of the Utah region, 1978-2000, showing the location and setting of the Wasatch Plateau-Book Cliffs coal mining region.

Figure 1-2

Location map of coal mines in the Wasatch Plateau and Book Cliffs coal fields.

Figure 2-1

Installation diagram for the broadband, 3-component, Guralp CMG-3T seismometer at the digital telemetry station SRU.

Figure 2-2

The four steps in the calibration procedure used to check and revise the manufacturer-supplied instrument response parameters for station SRU.

Figure 2-2

(continued).

Figure 2-2

(continued).

Figure 3-1

Location map of seismograph stations making up the University of Utah regional seismic network, July 2000.

Figure 3-2

Map showing the location of the Wasatch Plateau-Book Cliffs study area with respect to the distribution of stations in the University of Utah regional seismic network in 1994 (from Arabasz et al., 1997).

Figure 3-3

Existing and planned seismograph stations in the Wasatch Plateau-Book Cliffs area, July 2000.

Figure 3-4

Plots comparing values of corrected coda-duration magnitude (MC() to measured values of local Richter magnitude (ML).

Figure 3-5

Epicenter map of all seismic events located by the University of Utah regional seismic network in the WP-BC coal mining region from January 1, 1978, through June 30, 2000.

Figure 3-6

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1992.

Figure 3-7

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1993.

Figure 3-8

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1994.

Figure 3-9

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1995.

Figure 3-10

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1996.

Figure 3-11

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1997.

Figure 3-12

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1998.

Figure 3-13

Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1999.

Figure 3-14

Epicenter map of mining-related seismicity in the WP-BC coal mining region for January through June 2000.

Figure 3-15

Index map, keyed to Table 3-4, outlining areas of concentrated mining-related seismicity for which detailed characterizations are shown in Figures 3-16 through 3-21.

Figure 3-16

Temporal characterization of seismicity and coal production for S. Wasatch Plateau and S. Joes Valley sample areas identified in Figure 3-15.

Figure 3-17

Temporal characterization of seismicity and coal production for East Mountain and Rilda Canyon sample areas identified in Figure 3-15.

Figure 3-18

Temporal characterization of seismicity and coal production for Lower and Upper Huntington Canyon sample areas identified in Figure 3-15.

Figure 3-19

Temporal characterization of seismicity and coal production for Gentry Mountain and Pleasant Valley sample areas identified in Figure 3-15.

Figure 3-20

Temporal characterization of seismicity and coal production for Castle Gate and W. Book Cliffs sample areas identified in Figure 3-15.

Figure 3-21

Temporal characterization of seismicity and coal production for Central Book Cliffs and E. Book Cliffs sample areas identified in Figure 3-15.

Figure 4-1

Source mechanisms of mine seismicity.

Figure 4-2

Epicenter map (keyed to Table 4-1) of seismic events of magnitude 3.0 or larger in the WP-BC coal mining region, January 1978 through June 2000.

Figure 4-3

Plots of reduced travel time, time (sec) ( distance (km)/5.9 km/sec, versus distance in km for the March 7, 2000, ML 4.2 Willow Creek earthquake.

Figure 4-4

Plots of reduced travel time (reducing velocity is 5.9 km/sec) versus distance for the July 5, 1992, seismic event in the East Mountain area.

Figure 4-5

Focal mechanisms for the March 7, 2000, ML 4.2 Willow Creek earthquake determined for three different focal depths.

Figure 4-6

Focal mechanism for the February 5, 1998, ML 3.8 Willow Creek earthquake determined for a fixed focal depth of 0.62 km.

Figure 4-7

Focal mechanism for the June 2, 1996, ML 3.0 earthquake in the northern Wasatch Plateau, computed for the well-constrained focal depth of 11.0 ( 1.5 km (95% confidence limits).

Figure 4-8

Focal mechanisms for the May 14, 1981, ML´ 3.8 earthquake in the Gentry Mountain area at three different focal depths.

Figure 4-9

Focal mechanisms for the July 5, 1992, ML´ 3.5 earthquake in the East Mountain area at three different focal depths.

Figure 4-10

Comparison of SRU broadband recordings of the three seismic events in the trona mining area of southwestern Wyoming listed in Table 4-5.

APPENDICES

Appendix A

List of Mining-related Seismic Events > M 2.5 in the Wasatch Plateau-Book Cliffs Coal Mining Districts, January 1, 1978 to June 30, 2000

Appendix B

Quarterly Coal Mine Production for Mines in the Wasatch Plateau-Book Cliffs Coal Mining Districts, 1995-1998 - Compiled by Jefferson D. McKenzie

Appendix C

Documentation of Ground Truth for Significant Seismic Events Related to Underground Mining in Utah and Wyoming - by Michael K. McCarter

Figures C-1 to C-6

University of Utah Seismograph Stations «» 135 South 1460 East, Room 705 WBB
Salt Lake City, Utah 84112-0111 «» Phone 801-581-6274 «» Fax 801-585-5585
E-mail UUSS!

Table 2-1	Hardware and Calibration Information for Station SRU
Table 3-1	Correction Terms Used by Arabasz et al. (1997) for Revised Coda Magnitudes, MC´, in the Wasatch Plateau-Book Cliffs Area
Table 3-2	Correction Terms Used in This Report, Following Arabasz and Wyss (1999), for Revised Coda Magnitudes, MC´, in the Wasatch Plateau-Book Cliffs Area
Table 3-3	Seismic Events of Magnitude 3.0 or Greater in the WP-BC Coal-Mining Area, January 1978-June 2000, Ranked by Size
Table 3-4	Information for Sample Areas in Figure 3-15 Used to Investigate the Association of Seismicity with Mining in the WP-BC Area During the Period 1992-2000
Table 4-1	Focal-Mechanism and Summary Information for Seismic Events of Magnitude 3.0 or Larger in the WP-BC Coal-Mining Area, January 1978-June 2000, Ranked by Size
Table 4-2	The Willow Creek Composite Velocity Model
Table 4-3	The Trail Mountain Composite Velocity Model
Table 4-4	Data for Seismic Events in Table 4-1 Having Only Dilatational P-Wave First Motions
Table 4-5	Location and Focal Mechanism Information for Seismic Events of Magnitude 3.0 or Larger in the Trona-Mining District of Southwestern Wyoming, January - August 2000

Figure 1-1	Seismicity map of the Utah region, 1978-2000, showing the location and setting of the Wasatch Plateau-Book Cliffs coal mining region.
Figure 1-2	Location map of coal mines in the Wasatch Plateau and Book Cliffs coal fields.
Figure 2-1	Installation diagram for the broadband, 3-component, Guralp CMG-3T seismometer at the digital telemetry station SRU.
Figure 2-2	The four steps in the calibration procedure used to check and revise the manufacturer-supplied instrument response parameters for station SRU.
Figure 2-2	(continued).
Figure 2-2	(continued).
Figure 3-1	Location map of seismograph stations making up the University of Utah regional seismic network, July 2000.
Figure 3-2	Map showing the location of the Wasatch Plateau-Book Cliffs study area with respect to the distribution of stations in the University of Utah regional seismic network in 1994 (from Arabasz et al., 1997).
Figure 3-3	Existing and planned seismograph stations in the Wasatch Plateau-Book Cliffs area, July 2000.
Figure 3-4	Plots comparing values of corrected coda-duration magnitude (MC() to measured values of local Richter magnitude (ML).
Figure 3-5	Epicenter map of all seismic events located by the University of Utah regional seismic network in the WP-BC coal mining region from January 1, 1978, through June 30, 2000.
Figure 3-6	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1992.
Figure 3-7	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1993.
Figure 3-8	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1994.
Figure 3-9	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1995.
Figure 3-10	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1996.
Figure 3-11	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1997.
Figure 3-12	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1998.
Figure 3-13	Epicenter map of mining-related seismicity in the WP-BC coal mining region for the year 1999.
Figure 3-14	Epicenter map of mining-related seismicity in the WP-BC coal mining region for January through June 2000.
Figure 3-15	Index map, keyed to Table 3-4, outlining areas of concentrated mining-related seismicity for which detailed characterizations are shown in Figures 3-16 through 3-21.
Figure 3-16	Temporal characterization of seismicity and coal production for S. Wasatch Plateau and S. Joes Valley sample areas identified in Figure 3-15.
Figure 3-17	Temporal characterization of seismicity and coal production for East Mountain and Rilda Canyon sample areas identified in Figure 3-15.
Figure 3-18	Temporal characterization of seismicity and coal production for Lower and Upper Huntington Canyon sample areas identified in Figure 3-15.
Figure 3-19	Temporal characterization of seismicity and coal production for Gentry Mountain and Pleasant Valley sample areas identified in Figure 3-15.
Figure 3-20	Temporal characterization of seismicity and coal production for Castle Gate and W. Book Cliffs sample areas identified in Figure 3-15.
Figure 3-21	Temporal characterization of seismicity and coal production for Central Book Cliffs and E. Book Cliffs sample areas identified in Figure 3-15.
Figure 4-1	Source mechanisms of mine seismicity.
Figure 4-2	Epicenter map (keyed to Table 4-1) of seismic events of magnitude 3.0 or larger in the WP-BC coal mining region, January 1978 through June 2000.
Figure 4-3	Plots of reduced travel time, time (sec) ( distance (km)/5.9 km/sec, versus distance in km for the March 7, 2000, ML 4.2 Willow Creek earthquake.
Figure 4-4	Plots of reduced travel time (reducing velocity is 5.9 km/sec) versus distance for the July 5, 1992, seismic event in the East Mountain area.
Figure 4-5	Focal mechanisms for the March 7, 2000, ML 4.2 Willow Creek earthquake determined for three different focal depths.
Figure 4-6	Focal mechanism for the February 5, 1998, ML 3.8 Willow Creek earthquake determined for a fixed focal depth of 0.62 km.
Figure 4-7	Focal mechanism for the June 2, 1996, ML 3.0 earthquake in the northern Wasatch Plateau, computed for the well-constrained focal depth of 11.0 ( 1.5 km (95% confidence limits).
Figure 4-8	Focal mechanisms for the May 14, 1981, ML´ 3.8 earthquake in the Gentry Mountain area at three different focal depths.
Figure 4-9	Focal mechanisms for the July 5, 1992, ML´ 3.5 earthquake in the East Mountain area at three different focal depths.
Figure 4-10	Comparison of SRU broadband recordings of the three seismic events in the trona mining area of southwestern Wyoming listed in Table 4-5.

Appendix A	List of Mining-related Seismic Events > M 2.5 in the Wasatch Plateau-Book Cliffs Coal Mining Districts, January 1, 1978 to June 30, 2000
Appendix B	Quarterly Coal Mine Production for Mines in the Wasatch Plateau-Book Cliffs Coal Mining Districts, 1995-1998 - Compiled by Jefferson D. McKenzie
Appendix C	Documentation of Ground Truth for Significant Seismic Events Related to Underground Mining in Utah and Wyoming - by Michael K. McCarter
	Figures C-1 to C-6