Table 1 Event sequence at Twain Harte Dome from 2014 through 2016

From: Thermal influences on spontaneous rock dome exfoliation

Date (and time, when known) Event description Source
3 August 2014, 08:26 (PST) 1st exfoliation event C. Doty YouTubea & personal communication (8 Sept. 2014)
3 August 2014 Begin reservoir draining  
4 August 2014 End reservoir draining D. Wyckoff personal communication (22 Sept. 2014)
4 August 2014, 09:34 (PST) 2nd exfoliation event C. Doty YouTubeb & personal communication (8 Sept. 2014)
6 August 2014, 16:04 (PST) 3rd exfoliation event C. Doty YouTubec and personal communication (8 Sept. 2014), S. Lewis videod
20 August 2014, 01:20 (PST) 4th exfoliation event D. Wyckoff personal communication (22 Sept. 2014)
22 August 2014 Crackmeter instrumentation (CM1, CM2, CMC) installed  
4 September 2014, ~02:00 (PST) 5th exfoliation event D. Wyckoff personal communication (22 Sept. 2014)
2 October 2014 Crackmeter instrumentation (CM1, CM2, CMC) removed  
4 October 2014 Acoustic emissions monitoring (AE1-AE6) installed  
14–31 October 2014 Deep (~6 m) geotechnical drilling program Condor Earth Exploration Report, 12 Dec. 2014 [64]
17–18 November 2014 Shallow (~2 m) geotechnical drilling program Condor Earth Exploration Report, 12 Dec. 2014[64]
17 November 2014 Extensometer (EX1) installed  
25 March 2015 Acoustic emissions monitoring (AE1-AE6) removed  
1 April 2015 Dam repair begins  
16 April 2015 Begin reservoir filling Twain Harte Lake Association presentation, 18 July 2015 [65]
30 April 2015 Dam repairs completed  
May 2015 Removal of loose exfoliation slabs at top of dome  
8 June 2015 Reservoir filled Twain Harte Lake Association presentation, 18 July 2015 [65]
2–8 August 2015 6th exfoliation event—new cracking on rock and adjacent concrete D. Wyckoff personal communication (7 Aug. 2015)
March-April 2016 Geotechnical rockbolt installation on north side of dome  
24 May 2016 Instrumented rockbolts for uplift forces (RB1, RB2, RBC) installed.  
7 June 2016, 12:50 PST 7th exfoliation event S. Chung personal communication (8 June 2016)
22 July 2016, 18:25 PST 8th exfoliation event T. Gillespie personal communication (22 July 2016)
  1. a The Rock Cracks, http://youtu.be/zS_ffU0v2QA
  2. b The Rock Cracks Again, http://youtu.be/Oo6bAqgYa9g
  3. c Real-Time Granite Exfoliation—The Rock at Twain Harte Lake, https://www.youtube.com/playlist?list=PLQjk-QqHkYh3Wb0WM2KtjikuBR0OEonL7
  4. d See Supplementary Movie 1