WEBVTT 1 00:00:00.000 --> 00:00:02.583 (guitar music) 2 00:00:05.750 --> 00:00:06.610 Hi everyone. 3 00:00:06.610 --> 00:00:08.230 I'm Mike Poland, the scientist in charge 4 00:00:08.230 --> 00:00:09.700 of the Yellowstone Volcano Observatory 5 00:00:09.700 --> 00:00:13.230 and this is the monthly update for December 1st of 2020. 6 00:00:13.230 --> 00:00:15.210 Now before we get into talking about the monitoring data 7 00:00:15.210 --> 00:00:16.043 from the last month, 8 00:00:16.043 --> 00:00:17.730 I thought it might be fun to talk about 9 00:00:17.730 --> 00:00:19.980 the world's most famous geyser, Old Faithful. 10 00:00:21.450 --> 00:00:24.020 Most of us know Old Faithful as this very regular geyser, 11 00:00:24.020 --> 00:00:26.330 it erupts every hour and a half. 12 00:00:26.330 --> 00:00:27.970 But that didn't always use to be the case 13 00:00:27.970 --> 00:00:29.230 and in fact, there's some new research 14 00:00:29.230 --> 00:00:30.600 that suggests that there was a time 15 00:00:30.600 --> 00:00:32.850 when Old Faithful wasn't faithful at all. 16 00:00:32.850 --> 00:00:35.690 Now when it was first scientifically described in the 1870s, 17 00:00:35.690 --> 00:00:38.900 Old Faithful was erupting about every 60 to 70 minutes 18 00:00:38.900 --> 00:00:41.650 and that stayed mostly true through the 1950s. 19 00:00:41.650 --> 00:00:42.900 After a series of earthquakes 20 00:00:42.900 --> 00:00:46.600 starting with the 1959 magnitude 7.3 Hebgen Lake earthquake 21 00:00:46.600 --> 00:00:47.960 just outside the park, 22 00:00:47.960 --> 00:00:50.200 that interrupt interval between eruptions 23 00:00:50.200 --> 00:00:52.560 lengthened a little bit over time. 24 00:00:52.560 --> 00:00:54.220 And that gets us to our current interval today 25 00:00:54.220 --> 00:00:57.940 which is about 94 minutes plus or minus 10 minutes or so. 26 00:00:57.940 --> 00:01:00.720 About 2% of eruptions are very short duration, 27 00:01:00.720 --> 00:01:01.980 only about two-minute eruptions 28 00:01:01.980 --> 00:01:03.750 instead of the usual three to four minutes. 29 00:01:03.750 --> 00:01:05.230 And these eruptions are actually followed 30 00:01:05.230 --> 00:01:06.070 by very short intervals, 31 00:01:06.070 --> 00:01:07.810 only about an hour between eruptions 32 00:01:07.810 --> 00:01:08.690 which sorta makes sense, 33 00:01:08.690 --> 00:01:10.740 the geyser might not have erupted that much 34 00:01:10.740 --> 00:01:12.890 so it took less time to refill. 35 00:01:12.890 --> 00:01:14.250 But there's been new research 36 00:01:14.250 --> 00:01:16.810 that has looked at mineralized wood samples 37 00:01:16.810 --> 00:01:18.280 from the geyser cone itself. 38 00:01:18.280 --> 00:01:20.580 Now we know that trees are not gonna be growing on a geyser 39 00:01:20.580 --> 00:01:22.940 because of all that hot water, it kills them. 40 00:01:22.940 --> 00:01:25.050 So those trees must've grown at a time 41 00:01:25.050 --> 00:01:27.220 when Old Faithful was dormant 42 00:01:27.220 --> 00:01:29.160 and so by looking at the age of the trees, 43 00:01:29.160 --> 00:01:31.970 there were a number of tree specimens that were sampled. 44 00:01:31.970 --> 00:01:36.050 Scientists found a period about 600 to 800 years ago 45 00:01:36.050 --> 00:01:38.600 when the geyser must not have erupted at all. 46 00:01:38.600 --> 00:01:41.310 This actually corresponds to a period of drought 47 00:01:41.310 --> 00:01:42.143 in the region. 48 00:01:42.143 --> 00:01:43.150 In fact, drought throughout 49 00:01:43.150 --> 00:01:44.610 much of the Western United States. 50 00:01:44.610 --> 00:01:47.010 This might've also affected native societies 51 00:01:47.010 --> 00:01:48.790 in the Southwestern US. 52 00:01:48.790 --> 00:01:51.050 So during periods of heavy drought, 53 00:01:51.050 --> 00:01:53.120 when water levels perhaps are quite low 54 00:01:53.120 --> 00:01:56.110 beneath Old Faithful, the geyser doesn't interrupt at all. 55 00:01:56.110 --> 00:01:59.140 So quite some neat research coming out about Old Faithful 56 00:01:59.140 --> 00:02:02.030 and shows us that the times that we've been observing it, 57 00:02:02.030 --> 00:02:03.960 the last 150 years or so, 58 00:02:03.960 --> 00:02:05.210 it was really just a blip in time 59 00:02:05.210 --> 00:02:07.680 for this spectacular thermal feature. 60 00:02:07.680 --> 00:02:10.770 Okay, let's talk now about what happened over the last month 61 00:02:10.770 --> 00:02:12.850 in the Yellowstone region. 62 00:02:12.850 --> 00:02:14.780 The University of Utah Seismograph Stations 63 00:02:14.780 --> 00:02:16.870 which is responsible for the operation and maintenance 64 00:02:16.870 --> 00:02:18.460 of the Yellowstone Seismic Network 65 00:02:18.460 --> 00:02:21.040 located 100 earthquakes in the Yellowstone region 66 00:02:21.040 --> 00:02:22.580 during the month of November. 67 00:02:22.580 --> 00:02:23.420 That's pretty typical, 68 00:02:23.420 --> 00:02:25.340 background rates of seismicity for the area. 69 00:02:25.340 --> 00:02:26.590 You can see here that they're scattered 70 00:02:26.590 --> 00:02:27.560 throughout the region, 71 00:02:27.560 --> 00:02:28.880 although there is a bit of a cluster 72 00:02:28.880 --> 00:02:31.790 here between Hebgen Lake and the Norris Geyser Basin 73 00:02:31.790 --> 00:02:32.690 and that's pretty typical, 74 00:02:32.690 --> 00:02:35.460 this is the most seismically active area of the park. 75 00:02:35.460 --> 00:02:38.600 The largest earthquake of the month was a magnitude 3.1 76 00:02:38.600 --> 00:02:41.230 that occurred as a part of a small swarm 77 00:02:41.230 --> 00:02:43.370 of 12 events on November 25th 78 00:02:43.370 --> 00:02:45.750 right here on the Western boundary of the park 79 00:02:45.750 --> 00:02:48.393 so background rates of seismicity for the month. 80 00:02:49.720 --> 00:02:51.030 Turning now to defamation, 81 00:02:51.030 --> 00:02:55.220 this is vertical change at the White Lake GPS station 82 00:02:55.220 --> 00:02:57.460 which is on the East side of the caldera 83 00:02:57.460 --> 00:02:59.460 near the Sour Creek resurgent Dome. 84 00:02:59.460 --> 00:03:02.040 Each one of these dots is a single day's worth of data 85 00:03:02.040 --> 00:03:04.580 and this plot here spans two years. 86 00:03:04.580 --> 00:03:06.760 Downward trends indicates subsidence 87 00:03:06.760 --> 00:03:08.880 and upward trends indicate uplift. 88 00:03:08.880 --> 00:03:10.820 So you can see over these two years, 89 00:03:10.820 --> 00:03:13.800 the overall trend has been subsidence. 90 00:03:13.800 --> 00:03:16.640 The ground moving down at a rate of two to three centimeters 91 00:03:16.640 --> 00:03:18.440 about an inch or so every year 92 00:03:18.440 --> 00:03:21.330 and this trend has been ongoing since 2015. 93 00:03:21.330 --> 00:03:22.210 During the summer months, 94 00:03:22.210 --> 00:03:23.820 there are pauses in that subsidence 95 00:03:23.820 --> 00:03:25.500 due to groundwater recharge 96 00:03:25.500 --> 00:03:27.120 but overall, you can see the subsidence 97 00:03:27.120 --> 00:03:28.470 has been fairly persistent. 98 00:03:29.570 --> 00:03:31.520 Moving now to the West side of the caldera 99 00:03:31.520 --> 00:03:32.960 in the Mallard Lake resurgent Dome, 100 00:03:32.960 --> 00:03:35.910 this is the GPS station that's located near Old Faithful 101 00:03:35.910 --> 00:03:37.800 and the story is pretty much the same. 102 00:03:37.800 --> 00:03:40.680 Overall subsidence at rates of a couple of centimeters, 103 00:03:40.680 --> 00:03:42.950 slightly less than an inch per year 104 00:03:42.950 --> 00:03:46.113 and this has been ongoing since 2015. 105 00:03:47.520 --> 00:03:49.080 Now we move to the Norris Geyser Basin 106 00:03:49.080 --> 00:03:50.970 where we haven't seen much change, 107 00:03:50.970 --> 00:03:53.340 at least since the beginning of 2020. 108 00:03:53.340 --> 00:03:56.330 Norris had been uplifting from 2015 to 2018 109 00:03:56.330 --> 00:03:58.070 but that paused in 2018 110 00:03:58.070 --> 00:04:00.010 and since then there hasn't been much change at all, 111 00:04:00.010 --> 00:04:03.570 you can definitely see since January of 2020, 112 00:04:03.570 --> 00:04:05.200 there's been really no change whatsoever. 113 00:04:05.200 --> 00:04:09.120 So Norris defamation continues to be basically flat, 114 00:04:09.120 --> 00:04:11.053 no net change in that area. 115 00:04:12.030 --> 00:04:13.760 And finally going to everyone's favorite geyser, 116 00:04:13.760 --> 00:04:16.470 Steamboat Geyser that remains as active as ever 117 00:04:16.470 --> 00:04:19.590 with four eruptions during the month of November. 118 00:04:19.590 --> 00:04:21.060 Now this shows the temperature 119 00:04:21.060 --> 00:04:23.570 of the water in the geyser's outlet channel. 120 00:04:23.570 --> 00:04:26.470 These increases are minor geyser eruptions 121 00:04:26.470 --> 00:04:29.090 and they culminate in a spike that's a major eruption. 122 00:04:29.090 --> 00:04:30.240 After the major eruption, 123 00:04:30.240 --> 00:04:32.460 the geyser effectively goes dry for awhile 124 00:04:32.460 --> 00:04:33.960 and we just see air temperature 125 00:04:33.960 --> 00:04:35.410 being recorded in the outlet 126 00:04:35.410 --> 00:04:37.370 and then minor activity increases again 127 00:04:37.370 --> 00:04:39.680 building up to the next major eruption. 128 00:04:39.680 --> 00:04:43.270 Well the four major eruptions occurred on November 3rd, 129 00:04:43.270 --> 00:04:48.270 November 11th, November 20th and November 29th 130 00:04:48.440 --> 00:04:49.490 and with these four eruptions, 131 00:04:49.490 --> 00:04:53.720 that brings the grand total of eruptions for the year to 46. 132 00:04:53.720 --> 00:04:55.140 Well that does it for the monthly update 133 00:04:55.140 --> 00:04:56.340 for December of 2020. 134 00:04:56.340 --> 00:04:57.820 Now remember if you have any questions, 135 00:04:57.820 --> 00:05:00.090 you can feel free to email us anytime 136 00:05:00.090 --> 00:05:04.900 at yvowebteam, that's all one word, @usgs.gov. 137 00:05:04.900 --> 00:05:06.990 Hope everyone stays safe and stays healthy out there, 138 00:05:06.990 --> 00:05:10.080 just one month to go and then we're done with 2020. 139 00:05:10.080 --> 00:05:13.300 Take care everyone and see you in 2021. 140 00:05:13.300 --> 00:05:14.173 Bye bye. 141 00:05:14.173 --> 00:05:16.756 (guitar music)