Observed changes in geyser eruption intervals in Yellowstone following the 2002

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Carol Davidson
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1 DR 47 Observed changes in geyser eruption s in Yellowstone following the 2 Denali fault earthquake We monitored eruption s of geysers during the winter 2-3 by placing temperature sensors in the runoff channels. All instrumented geysers were located at the main Yellowstone geyser basins (Lower, Upper, and West Thumb s) that had been subject to the increase in earthquake activity (Fig. ). Data were not available from Norris due to instrument loss. Of these instrumented geysers, displayed notable changes in their eruption s, i.e. the changes were larger than the standard error of the s the Denali earthquake. Four geysers were too erratic to show any effects, and geysers showed no significant changes. There was no common pattern in geyser response to the Denali earthquake. But the most obvious examples were Daisy (Fig. 2), Depression, and Riverside geysers in Upper, which showed a rapid decrease in their eruption within hours following the Denali earthquake, recovering close to pre-denali eruption s over subsequent weeks. Castle in Upper responded by having an unusually large number of minor eruptions that do not complete the full expected minute water phase and 3-4 minute steam phase. Starting on ember there was one week with no minor eruptions followed by two weeks with a large number of minor eruptions. Pink in Lower, and Plate and Plume s in Upper displayed only short-term (few days) irregularities in their eruption behavior lasting for a few days. Lone Pine in West Thumb, on the other hand, showed a gradual increase in eruption s that peaked three weeks after the Denali earthquake. Page of 6

2 DR 47 7: : Eruption 6: no data 5: 4: 5:37:2 (5:37:3) 5:25:5 (5:23:) A) Pink, Lower Eruption : 6: 2: : 4: : 2::4 (2::5) :5:32 (4:2:3) B) Castle, Upper 2: Eruption 3: 2: : 2:3:2 (2:39:47) :57:4 (:36:46) C) Daisy, Upper Eruption : : 9: : 7: 6: 5: :: (::) 7::4 (7:23:3) D) Depression, Upper Figure. eruption s of Yellowstone between tember and 3 ember 3 influenced by Denali fault earthquake (). A, C H: Gray lines are raw data (individual eruption s), and black lines are smoothed data (moving median over several data points). B: Gray line denotes minor eruption s, and black line denotes major eruption s. Median eruption s and after Denali fault earthquake are shown in hour:minute:second (h:min:s) format. Median eruption s and after Denali fault earthquake are computed over several weeks and over a few days (in parentheses), respectively. Time of earthquake is marked by bold gray line. Page 2 of 6

3 DR 47 Eru[tion Eruption 9: : 7: 6: 5: 4: 3: 2: : 2:33:42 (2:36:7) 3:: (3::43) E) Plate, Upper 7: 6: 5: 6:2:56 (6:36:44) 6:: (5:57:4) G) Riverside, Upper Eruption Eruption 2: : :3 : :3 eruption of Giantess :47:6 (:46:) :44:9 (:44:) F) Plume, Upper 4: 44: 4: 36: 32: 2: : : 6: 2: : :9:44 2:4:5 dormant H) Lone Pine, West Thumb Figure. continued. Page 3 of 6

4 DR 47 TABLE : SHORT-TERM (FEW DAYS) CHANGES IN ERUPTION INTERVALS OF MONITORED GEYSER PRIOR TO AND AFTER THE DENALI FAULT EARTHQUAKE (). A NEGATIVE CHANGE INDICATES THAT ERUPTION INTERVAL DECREASED FOLLOWING THE DENALI FAULT EARTHQUAKE. Norris Time period (days) after No data available after Lower Fountain Great Fountain Pink 5 5:37 : 5:23 :9 -:4-4. Upper (%) Boardwalk Castle 2:9 :4 4:2 :2 +:53 +. Daisy 5 2:4 : :37 :5 -:3-39. Depression 7 : :36 7:23 :42 -: -2. Grand Grotto Lion North Goggle Oblong Old Faithful Plate 7 2:36 : 3:2 : +: Plume 7 :46 :3 :44 :3 -:2-4. Riverside 3 6:37 :4 5:57 :2 -:4 -. Rift West Triplet West Thumb Lone Pine 7 2:4 3: 26:26 5:4 +5: +26. Resurgent Generic Hillside Page 4 of 6

5 DR 47 TABLE 2: LONG-TERM (SEVERAL DAYS) CHANGES IN ERUPTION INTERVALS OF GEYSER FOR WHICH DATA WAS AVAILABLE PRIOR TO AND AFTER THE DENALI FAULT EARTHQUAKE (). A NEGATIVE CHANGE INDICATES THAT ERUPTION INTERVAL DECREASED FOLLOWING THE DENALI FAULT EARTHQUAKE. Norris Lower Time period (days) after No data available after Fountain Great Fountain Pink 4 5:37 : 5:25 :9 -:2-4. Upper (%) Boardwalk Castle 5 2:25 :25 :6 : +:4 +6. Daisy 5 2:3 :2 :5 :4 -:7-33. Depression 57 :3 2:2 7:56 2:6 -:42 -. Grand Grotto Lion North Goggle Oblong Old Faithful Plate 33 2:34 :2 3: :47 +: Plume 3 :47 :6 :44 :3 -:3-6. Riverside 53 6: :2 6: : -:6-4. Rift West Triplet West Thumb Lone Pine 62 : :4 2: :52 +7: Resurgent Generic Hillside Page 5 of 6

6 DR 47 Observed increases in seismicity at major geyser basin following the 2 Denali earthquake Mc >. Mc >. A) Yellowstone Lake B) West Thumb Mc >. 3 Mc > C) Upper D) Norris Figure 2. of earthquakes at major geyser basins in Yellowstone following the 2 Denali earthquake (). A: northern part of Yellowstone Lake, B: West Thumb, C: Upper, D: Norris. Inlay diagrams show cumulative number of earthquakes with magnitude >. from 994 to present for each geyser basin. Time of the is indicated by grey line. Page 6 of 6

from Stacy Vallie on 22 February 2007, 9:04 am. from Carolyn Loren on 22 February 2007, 14: February 2007

from Stacy Vallie on 22 February 2007, 9:04 am. from Carolyn Loren on 22 February 2007, 14: February 2007 Analysis of a Suggested Major Eruption of Steamboat Geyser on 21 February 2007 Hank Heasler Cheryl Jaworowski Geology Program Yellowstone National Park Summary Individuals touring Norris Geyser Basin on