YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE June, 1, 2009

YELLOWSTONE VOLCANO
44.43°N 110.67°W
Summit Elevation 9203 ft (2805 m)
Volcano Alert Level: NORMAL
Aviation Color Code: GREEN
May 2009 Yellowstone Seismicity Summary
During the month of May 2009, 133 earthquakes were located in the Yellowstone region.
The largest event was a magnitude 3.0 on May 25 at 4:41 AM MDT, located about 5 miles southeast of Madison Junction, YNP. This event was part of a small earthquake swarm that, included 68 events on May 25 begining about 3 AM and stopping before 2PM local time. The magnitudes during the swarm ranged from 3.0 to 0.2.
Earthquake activity in the Yellowstone region is at relatively normal background levels.
Ground Deformation Summary
Through May 2009, continuous GPS data show that uplift of the Yellowstone Caldera has slowed but may be continuing. The WLWY station, located in the northeastern part of the caldera, has undergone a total of ~23 cm of uplift since mid-2004. Its record can be found at:
http://pboweb.unavco.org/shared/scripts/stations/?checkkey=WLWY&sec=timeseries_plots&timeseries=raw
The currently observed reduction in uplift rate may be related to seasonal changes related to snowmelt and groundwater recharge. In several of the past 5 years, such changes have caused decreased uplift or slight subsidence, but were followed later in the year by continued uplift. The general uplift of the Yellowstone caldera is of scientific importance and will continue to be monitored closely by YVO staff.
An article on the current uplift episode at Yellowstone and discussion of long-term ground deformation at Yellowstone and elsewhere can be found at: http://volcanoes.usgs.gov/yvo/publications/2007/upsanddowns.php
The Yellowstone Volcano Observatory (YVO) is a partnership of the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.


Rapport mensuel de l'Observatoire du Parc National Yellowstone (USA) sur l'activité du volcan Yellowstone.
133 évènements sismique enregistrés dans la région du Yellowstone en mai 2009 d'une magnitude maxi de 3,0 et mini de 0,2.
La Déformation du sol en revanche est à ses plus bas niveau mais il n'est pas impossible qu'elle se renforce prochainement.
Le parc de Yellowstone est le plus grand domaine du monde interessé par les phénomènes termaux liés au volcanisme.


Rapporto mensile dell'Osservatorio del Parco Yellowstone (USA) sull'attività del vulcano Yellowstone.
133 eventi sismici registrati nella regione del Yellowstone in maggio 2009 di un magnitudo compreso tra 0,2 e 3,0.
La deformazione del suolo è stata minima anche se potrebbe verificarsi unnto in un prossimo futuro.
Il Parco del Yellowstone è il più grande areale del mondo interessato da fenomeni termali legati al vulcanesimo.