quote:
Earthquake swarm just another day in YellowstoneA swarm of earthquakes in Yellowstone National Park has seismographs quivering and scientists tracking the movements in hopes of understanding even more about the area’s underlying geology.
An earthquake swarm may sound ominous, but in fact swarms are quite normal in Yellowstone and are more a matter of scientific interest than concern, according to Dina Venezky of the USGS Volcano Science Center in Menlo Park, Calif.
Geologists make a distinction between a swarm or sequence of earthquakes and a single event with aftershocks, she said.
When there is a single large earthquake, such as the one in Haiti last week, aftershocks occur at decreasing magnitudes after the original event, she said.
During a swarm, however, the magnitudes of the first earthquakes in the sequence are lower, increasing toward the middle of the swarm and decreasing again until they peter out.
There is still much to be learned about earthquakes in general, but Venezky said each one gives scientists an opportunity to glimpse what is going on underground.
The current swarm is a result of tectonic stresses, according to Robert Smith, a seismologist at the University of Utah. As plates of the outer layer of the Earth’s crust shift, they accumulate stresses along fault lines, which, when released, cause an earthquake.
It is possible, Venezky said, that earthquakes in a swarm trigger each other, but seismologists are as yet unsure of that effect.
The largest earthquake in the current swarm had a magnitude of 3.7, according to the University of Utah seismograph stations. As of 3 p.m. Tuesday, there had been 469 earthquakes recorded in the swarm, five with magnitudes above 3.0.
“Earthquake swarms are completely normal for Yellowstone,” Venezky said. “In fact, around 40 percent of the region’s earthquakes are part of a swarm.”
She said swarms can normally last from a few days to a few weeks. In last year’s Yellowstone Lake swarm, 900 earthquakes were recorded between Dec. 26, 2008, and Jan. 8, 2009.
A longer swarm in 1985 lasted for a few months, however, so seismologists are unable to predict when a swarm will end.
Hydrothermal activity, which can be another cause of earthquakes, is associated with the ancient volcanic caldera beneath Yellowstone, but because the current swarm is a result of tectonic stress, Venezky said it is unlikely it is a precursor to volcanic activity.
“There have been so many swarms on record and the last volcanic eruption was about 70,000 years ago,” Venezky said.
During the course of the swarm, seismologists will continue to track the earthquakes for future analysis.
To see updates of recorded earthquakes in the swarm, Smith recommends the University of Utah seismograph stations Web site,
www.seis.utah.edu, where maps and seismograph readings are available.
quote:
MAP 2.5 2010/01/21 07:48:34 44.580 -110.975 9.5 14 km ( 9 mi) SE of West Yellowstone, MT
MAP 3.7 2010/01/21 06:16:19 44.568 -110.973 10.3 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 3.6 2010/01/21 06:01:51 44.568 -110.979 9.7 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.7 2010/01/21 01:19:47 44.569 -110.976 9.9 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.9 2010/01/20 21:43:01 44.571 -110.974 9.4 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/20 20:10:21 44.562 -110.974 8.5 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/20 20:00:28 44.564 -110.974 9.2 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.3 2010/01/20 14:27:23 44.561 -110.968 9.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.2 2010/01/20 08:27:25 44.563 -110.972 8.8 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/20 04:43:50 44.569 -110.972 10.4 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.8 2010/01/20 04:42:53 44.566 -110.950 12.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/20 04:42:18 44.565 -110.959 10.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.8 2010/01/20 04:41:42 44.557 -110.951 11.8 17 km ( 11 mi) SE of West Yellowstone, MT
MAP 3.3 2010/01/20 04:41:03 44.569 -110.966 9.2 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/20 04:13:20 44.579 -110.896 18.3 19 km ( 12 mi) ESE of West Yellowstone, MT
MAP 2.5 2010/01/20 04:12:28 44.569 -110.967 9.3 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.6 2010/01/20 04:12:03 44.572 -110.959 10.8 15 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/20 01:48:11 44.556 -110.965 10.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.4 2010/01/20 01:45:02 44.553 -110.970 9.8 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/20 01:40:38 44.555 -110.966 10.8 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 3.2 2010/01/20 01:35:37 44.561 -110.968 9.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.2 2010/01/20 01:11:51 44.558 -110.972 10.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/20 01:01:38 44.564 -110.965 9.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.1 2010/01/20 00:55:25 44.560 -110.951 11.5 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.4 2010/01/20 00:38:00 44.556 -110.972 9.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.1 2010/01/20 00:29:15 44.550 -110.961 6.5 17 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/20 00:27:02 44.560 -110.960 10.2 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/20 00:13:04 44.563 -110.965 10.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.8 2010/01/20 00:07:10 44.566 -110.972 10.2 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/19 21:33:24 44.553 -110.966 8.3 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 3.5 2010/01/19 21:32:31 44.562 -110.974 9.3 15 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.1 2010/01/19 21:32:11 44.563 -110.970 8.3 15 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.4 2010/01/19 21:07:05 44.552 -110.975 9.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 3.3 2010/01/19 16:48:32 44.566 -110.965 6.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.3 2010/01/19 13:39:13 44.559 -110.968 0.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.6 2010/01/19 13:26:52 44.561 -110.966 9.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.6 2010/01/19 10:36:14 44.567 -110.963 9.8 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/19 09:40:45 44.565 -110.954 10.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.4 2010/01/19 09:39:57 44.562 -110.972 10.0 15 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.2 2010/01/19 05:52:23 44.557 -110.963 9.6 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.3 2010/01/19 05:39:06 44.568 -110.975 8.3 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.1 2010/01/19 04:43:18 44.562 -110.956 10.2 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 3.0 2010/01/19 04:42:14 44.569 -110.968 9.8 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 3.4 2010/01/19 03:39:39 44.566 -110.969 10.2 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/19 02:14:23 44.571 -110.970 8.2 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.9 2010/01/19 02:07:28 44.558 -110.969 9.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/19 01:18:50 44.565 -110.963 10.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/19 00:56:09 44.395 -110.827 1.0 37 km ( 23 mi) SE of West Yellowstone, MT
MAP 1.6 2010/01/19 00:21:06 44.556 -110.968 9.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.8 2010/01/18 23:56:32 44.562 -110.965 9.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.6 2010/01/18 23:43:35 44.563 -110.961 9.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/18 23:04:39 44.559 -110.958 10.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.8 2010/01/18 22:49:56 44.566 -110.970 9.6 15 km ( 9 mi) SE of West Yellowstone, MT
MAP 1.4 2010/01/18 22:46:37 44.558 -110.966 10.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 22:36:08 44.562 -110.960 10.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.4 2010/01/18 20:50:49 44.560 -110.966 9.2 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.3 2010/01/18 20:46:03 44.562 -110.961 10.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.9 2010/01/18 19:38:42 44.563 -110.963 10.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 3.1 2010/01/18 18:03:14 44.560 -110.969 9.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/18 16:00:57 44.564 -110.968 9.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.6 2010/01/18 16:00:14 44.560 -110.969 8.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 11:40:11 44.812 -111.523 4.5 37 km ( 23 mi) WNW of West Yellowstone, MT
MAP 2.5 2010/01/18 10:10:42 44.557 -110.966 7.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.9 2010/01/18 10:10:22 44.558 -110.962 8.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.4 2010/01/18 02:53:13 44.541 -110.955 13.0 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 02:45:33 44.547 -110.958 11.6 17 km ( 11 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/18 02:44:36 44.556 -110.964 8.6 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.1 2010/01/18 02:39:20 44.561 -110.962 9.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.7 2010/01/18 02:38:01 44.562 -110.968 8.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/18 01:04:24 44.559 -110.968 7.3 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 00:32:46 44.555 -110.959 9.2 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 00:31:35 44.550 -110.967 8.9 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.2 2010/01/18 00:24:45 44.558 -110.965 9.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.7 2010/01/18 00:02:56 44.557 -110.967 8.8 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/18 00:02:12 44.543 -110.957 11.8 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.1 2010/01/17 23:50:32 44.546 -110.965 12.5 17 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/17 23:37:56 44.550 -110.969 9.2 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.3 2010/01/17 23:35:50 44.560 -110.965 9.2 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.4 2010/01/17 23:29:07 44.551 -110.969 8.8 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/17 23:17:43 44.558 -110.961 9.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.2 2010/01/17 23:06:02 44.557 -110.962 7.5 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/17 22:43:33 44.557 -110.966 7.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.5 2010/01/17 21:55:59 44.556 -110.965 7.4 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/17 21:15:56 44.556 -110.965 9.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.7 2010/01/17 21:04:07 44.557 -110.966 8.7 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.2 2010/01/17 21:01:46 44.556 -110.957 9.1 17 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.9 2010/01/17 20:56:37 44.557 -110.963 8.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.0 2010/01/17 20:50:18 44.556 -110.966 9.0 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 2.1 2010/01/17 20:38:02 44.554 -110.965 8.6 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/17 20:23:12 44.552 -110.959 9.4 17 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.0 2010/01/17 20:17:57 44.544 -110.957 11.2 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/17 00:19:36 44.573 -110.923 3.8 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/16 22:20:09 44.571 -110.917 4.3 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/16 20:38:52 44.571 -110.889 6.9 20 km ( 12 mi) ESE of West Yellowstone, MT
MAP 1.0 2010/01/16 09:56:07 44.566 -110.923 6.4 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.3 2010/01/16 09:22:45 44.571 -110.922 5.5 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.2 2010/01/16 09:18:04 44.569 -110.924 7.2 18 km ( 11 mi) SE of West Yellowstone, MT
MAP 1.7 2010/01/16 05:52:38 44.578 -110.936 5.9 16 km ( 10 mi) SE of West Yellowstone, MT
MAP 1.5 2010/01/15 09:11:34 44.574 -110.927 4.5 17 km ( 11 mi) SE of West Yellowstone, MT