From: abmac@dslextreme.com   
      
   Brian Handwerk   
   for National Geographic News   
   Published January 19, 2011   
   Yellowstone National Park's supervolcano just took a deep "breath,"   
   causing miles of ground to rise dramatically, scientists report.   
   The simmering volcano has produced major eruptions—each a thousand times   
   more powerful than Mount St. Helens's 1980 eruption—three times in the   
   past 2.1 million years. Yellowstone's caldera, which covers a 25- by   
   37-mile (40- by 60-kilometer) swath of Wyoming, is an ancient crater   
   formed after the last big blast, some 640,000 years ago.   
   (See "When Yellowstone Explodes" in National Geographic magazine.)   
   Since then, about 30 smaller eruptions—including one as recent as 70,000   
   years ago—have filled the caldera with lava and ash, producing the   
   relatively flat landscape we see today.   
   But beginning in 2004, scientists saw the ground above the caldera rise   
   upward at rates as high as 2.8 inches (7 centimeters) a year. (Related:   
   "Yellowstone Is Rising on Swollen 'Supervolcano.'")   
   The rate slowed between 2007 and 2010 to a centimeter a year or less.   
   Still, since the start of the swelling, ground levels over the volcano   
   have been raised by as much as 10 inches (25 centimeters) in places.   
   "It's an extraordinary uplift, because it covers such a large area and   
   the rates are so high," said the University of Utah's Bob Smith, a   
   longtime expert in Yellowstone's volcanism.   
      
      
   /////   
      
      
   Yellowstone Caldera – Volcanic traces and seismic activity   
   Large segments of Yellowstone National Park are in the area of the   
   caldera, part of the Yellowstone volcano. Some 640,000 years ago,   
   approximately eight kilometres below ground, a huge caldera magma   
   chamber was formed. It is approximately 60 kilometres long and 40   
   kilometres wide and ten kilometres thick. Because of these dimensions,   
   the Yellowstone volcano is one of the super-volcanoes and has been   
   active for 17 million years.   
      
   Three major eruptions   
   In the area of Yellowstone National Park are the remains of three   
   overlapping calderas, which are attributed to three major eruptions. The   
   largest eruption was Huckleberry Ridge which eruption 2.1 million years   
   ago. In that outbreak, 2,500 square kilometres of volcanic material was   
   ejected creating a caldera, formed by a scale of 80 by 50 kilometres.   
   Relics of that eruption are the surface basalts, which originated from   
   cooled lava. At the Mesa Falls eruption, 1.3 million years ago, only 280   
   square kilometres of volcanic material was ejected. From this outbreak   
   came the Island Park Caldera. The last major eruption, the Lava Creek   
   eruption some 640,000 years ago, created the present-day Yellowstone   
   caldera, with a length of 40 kilometres and a width of 25 kilometres. In   
   that outbreak, 1,000 square kilometres of volcanic material was ejected.   
    From the volcanic ash tuffs emerged rhyolites from the cooled magma.   
   Since the last big eruption, there have been more than 30 volcanic   
   eruptions, which coated the rock stratas with rhyolite. The rhyolites   
   now form an area of 340 square kilometres. Another outpouring of magma   
   formed the Sour Creek dome in the northeast of the caldera and the   
   Mallard Lake dome in the south of the caldera. Both domes rise today by   
   two to seven centimetres per year.   
      
   Present tectonics and seismics   
   Yellowstone National Park is an area of high tectonic activity, which is   
   crossed by numerous faults and repeatedly struck by mostly small   
   earthquakes. In the Lake earthquake of 1959, the hedging reached a   
   magnitude of 7.5. In 1975, the Norris earthquake reached a magnitude of   
   6.1. Nearly two thirds of existing worldwide hot springs are located in   
   the Yellowstone area. In total, there are over 10,000 hot springs. The   
   most famous geyser is Old Faithful. Every 60 to 90 minutes, an explosive   
   fountain erupts throwing up to 32,000 litres of hot water at a height of   
   up to 55 metres. The Steamboat Geyser is the largest active geyser in   
   the world. Its fountain reaches a height of approximately 130 metres.   
   There are sometimes several years between the individual eruptions.   
      
   Continental divide   
   The main watershed of North America flows through the southwestern part   
   of Yellowstone National Park, its tributaries flow to the Pacific Ocean   
   via the Gulf of Mexico and thus separates the Atlantic Ocean. While the   
   Yellowstone River flows northward and drains through the Missouri and   
   from the Mississippi into the Gulf of Mexico, the Snake River flows   
   south, draining into the Pacific.   
   H. Kiegel; Ü: C. Fleming   
      
   ////   
      
   Earthquakes recorded by University of Utah Seismograph Stations for the   
   last week (168 hours). Times are local (MST or MDT). Most recent   
   earthquakes are at the top of the list. Click on the word "map" or "MAP"   
   to see a map view. Click on a "DATE" to get additional text information.   
   Magnitude 3 and greater earthquakes are printed in bold type. The top   
   three magnitudes greater than or equal to 3 are in red.   
        MAG    DATE    LOCAL-TIME  LAT     LON    DEPTH    LOCATION   
               y/m/d     h:m:s     deg     deg     km   
      
   map 1.5  2012/05/25 07:14:19 44.367N 110.836W  1.6   39 km (24 mi) SSE   
   of  West Yellowstone, MT   
   map 2.0  2012/05/24 17:34:38 38.221N 112.326W  2.0    7 km ( 5 mi) NW   
   of  Circleville, UT   
   map 1.5  2012/05/24 11:43:11 38.254N 108.822W  0.4   23 km (14 mi) W   
   of  Naturita, CO   
   map 2.1  2012/05/24 00:47:30 44.153N 110.323W  7.9   70 km (43 mi) NE   
   of  Alta, WY   
   map 0.5  2012/05/24 00:41:27 44.144N 110.336W  2.6   68 km (42 mi) NE   
   of  Alta, WY   
   map 1.5  2012/05/23 22:19:17 39.434N 111.199W  0.0   23 km (14 mi) WNW   
   of  Huntington, UT   
   map 1.2  2012/05/22 23:15:30 45.679N 112.065W  7.2   21 km (13 mi) S   
   of  Whitehall, MT   
   map 1.4  2012/05/21 14:55:28 41.142N 112.912W  5.2   67 km (41 mi) W   
   of  Hooper, UT   
   map 0.9  2012/05/21 11:50:56 41.139N 112.926W  4.7   68 km (42 mi) W   
   of  Hooper, UT   
   map 0.6  2012/05/21 11:29:59 44.585N 110.351W  2.1   58 km (36 mi) SSE   
   of  Gardiner, MT   
   map 1.7  2012/05/21 07:59:53 39.711N 111.262W  8.6    9 km ( 6 mi) W   
   of  Scofield, UT   
   map 1.0  2012/05/21 05:59:32 44.423N 110.400W  7.0   62 km (38 mi) ESE   
   of  West Yellowstone, MT   
   map 1.7  2012/05/21 03:50:05 38.009N 111.096W  0.3   31 km (19 mi) ENE   
   of  Boulder, UT   
   map 1.2  2012/05/21 02:30:46 38.233N 112.319W  2.4    8 km ( 5 mi) NNW   
   of  Circleville, UT   
   map 1.2  2012/05/20 12:58:46 45.534N 111.898W  6.0   21 km (13 mi) SSW   
   of  Harrison, MT   
      
   73,000 BC Toba Volcano 99% die off of humans The lake is 100 kilometres   
   long and 30 kilometres wide or 62 by 18 miles or 1116 sq miles   
      
   640,000 BC Yellowstone Caldera Third Time record. The major features of   
   the caldera measure about 34 by 45 miles (55 by 72 km) or 1520 sq miles.   
      
   1.3 million BC Yellowstone Caldera Second Time record   
      
   2.1 million Yellowstone Caledera First time record.   
      
   2.7 million BC Stone Tools   
      
   3.0 million BC Fire   
      
      
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