The extraordinary expansion of Yellowstone caldera volcano

Maps pools tremors on Yellowstone Lake in 2008-09. A. Location of earthquakes on the northern end of Yellowstone Lake, with the direction of the deep fault, which was modeled as a vertical volcanic zherlovina. Shown seismic data and offset soil. B. Model zherloviny expansion at different rates (major and minor), explaining the model and the corresponding displacement of the seismic activity. Reprinted from Farrell and others (2010; Geophysical Research Letters). Click to enlarge the picture.

Researchers from the University of Utah have recently published two new articles in the journal Geophysical Research Letters, dedicated to the active nature of the Yellowstone volcanic and hydrothermal system. In the first article, a graduate student Jamie Farrell (Jamie Farrell) and colleagues examined research a large number of tremors in Yellowstone in late 2008 — early 2009.

In addition to a full description of the characteristics of a pool of aftershocks in the article described as the largest and deepest of the earthquake, which had an unusual volumetric (explosive) behavior, consistent with the movement of the fluid from the depths to the surface hydrothermal systems (depth of less than 6.5 km and 5 km).

In addition, a careful analysis of the overlapping sequences GPS data by Yellowstone revealed a marked horizontal expansion soil (up to 7 mm) on the surface, consistent with the expansion of the fault near the lake.

A similar behavior was inherent in the very large pool of tremors in Yellowstone in 1985 in the western part of the Yellowstone Plateau, and may be even more similar than is commonly believed.

The authors suggest the possibility that this style of behavior is the key to understanding the hydrothermal explosions, large earthquakes and even volcanic eruptions.

The second article is written by Wu-Lung Chang (Wu-Lung Chang), associate professor of the Central National Taiwan University and Research Associate at the University of Utah and colleagues from the University of Utah. It discusses the temporal properties of the accelerated uplift of the caldera in 2004-2010, and drew attention to the period slow rise.

As in their previous work, the authors simulated the rising and have come to the conclusion that it was caused by the horizontal extension of the volcanic bed near the top of the subsurface (7-10 km) Magma pocket.

In the new paper, the authors conclude that, since 2006, the nature of soil deformation revealed a time delay rises, decreasing from south-east to north-west through the caldera.

Such a move could be due to smaller volumes of magma deep podpitok and the fluid pressure or release of Yellowstone Lake, relating to 2008 and the recent tremors pools (2010) on the plateau of Madison.

The comparison between earthquakes and ground uplift Yellowstone caldera in 2003-2010, respectively. Raising GPS-stations and WLWY OFW2 shown by the blue lines (for comparison, the blue scale, the vertical movement, cm). Histogram (gray bars) reflects the number of tremors in Yellowstone by month (right axis Y), with the main activity at a time when raising start to slow down. Reprinted from Chang and others (2010; Geophysical Research Letters).

List of references:
· Chang, W., RB Smith, C. Wicks, C. Puskas, and J. Farrell, 2007, Accelerated uplift and source models of the Yellowstone caldera, 2004-2006, From GPS and InSAR observations, Science 9 November 2007: Vol. 318. no. 5852, pp. 952 — 956 DOI: 10.1126/science.1146842.

· Chang, W. -L., Smith, RB, Farrell, J., and Puskas, CM, 2010, An extraordinary episode of Yellowstone caldera uplift, 2004-2010, from GPS and InSAR observations: Geophysical Research Letters, v. 37, L23302, doi: 10.1029/2010GL045451.

· Farrell, J., Smith, RB, Taira, T., Chang, W. -L., And Puskas, CM, 2010, Dynamics and rapid migration of the energetic 2008-2009 Yellowstone Lake earthquake swarm: Geophys. Res. Lett., 37, L19305, doi: 10.1029/2010GL044605.

· Waite, GR and Smith, RB, 2002, Seismic evidence for fluid migration accompanying subsidence of the Yellowstone Caldera: Journal of Geophysical Research, v. 107, no. B9, p. 2177, 10.1029/2001JB000586.

Translation: Co.
Source: USGS

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