A deep low-velocity body under the Yellowstone caldera, Wyoming: Delineation using teleseismic P-wave residuals and tectonic interpretation

Iyer, H. M.; Evans, John R.; Zandt, G.; Stewart, R. Meldrum; Coakley, John M.; Roloff, J. N.

doi:10.1130/gsab-p2-92-1471

Cited by 42 publications

(26 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Maybe a closer analogue to Hawaii is the Snake River Yellowstone volcanic system, which is situated on continental lithosphere and exhibits a mixture of extensive basaltic volcanism and a northeastward progression of silicic volcanism (as opposed to the purely basaltic volcanism with a clear southeast progression in Hawaii). Immediately beneath Yellowstone National Park, the most active region, the low‐velocity anomaly extended from the surface to a depth of at least 250 km (Iyer et al 1981), whereas along a profile across the Eastern Snake River Plain ∼200 km from the active centre no anomalous velocities were observed in the crust and uppermost lithosphere and low velocities were only found in the deeper lithosphere and asthenosphere (Evans 1982), consistent with a moving magmatic centre and cooling from the top.…”

Section: Introductionmentioning

confidence: 98%

“…Tomographic images of upper mantle structure have also been generated in other hotspot locations, for example in Iceland (Wolfe et al 1997; Foulger et al 2000; Allen et al 2001) and Yellowstone (Iyer et al 1981; Evans 1982; Iyer 1984). All of these studies observed low‐velocity anomalies of magnitudes a few per cent of the P ‐wave velocity beneath volcanically active regions, which were interpreted to be due to increased temperatures and in some cases to partial melting.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography

Tilmann

Benz

Okubo

2001

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARY We examine the P‐wave velocity structure beneath the island of Hawaii using P‐wave residuals from teleseismic earthquakes recorded by the Hawaiian Volcano Observatory seismic network. The station geometry and distribution of events makes it possible to image the velocity structure between ∼40 and 100 km depth with a lateral resolution of ∼15 km and a vertical resolution of ∼30 km. For depths between 40 and 80 km, P‐wave velocities are up to 5 per cent slower in a broad elongated region trending SE–NW that underlies the island between the two lines defined by the volcanic loci. No direct correlation between the magnitude of the lithospheric anomaly and the current level of volcanic activity is apparent, but the slow region is broadened at ∼19.8°N and narrow beneath Kilauea. In the case of the oceanic lithosphere beneath Hawaii, slow seismic velocities are likely to be related to magma transport from the top of the melting zone at the base of the lithosphere to the surface. Thermal modelling shows that the broad elongated low‐velocity zone cannot be explained in terms of conductive heating by one primary conduit per volcano but that more complicated melt pathways must exist.

show abstract

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography

Tilmann

Benz

Okubo

2001

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

“…Perhaps the most compelling evidence against a plume source for Yellowstone has been the lack of a clear seismic image of the plume in regional P wave tomography studies [ Evans and Iyer , 1979; Iyer et al , 1981; Dueker and Humphreys , 1990; Humphreys and Dueker , 1994a, 1994b; Christiansen et al , 2002]. While these studies show a low‐velocity anomaly to at least 200 km depth, the limitations in the data may preclude resolution of deeper anomalies.…”

Section: Introductionmentioning

confidence: 99%

Models of lithosphere and asthenosphere anisotropic structure of the Yellowstone hot spot from shear wave splitting

2005

View full text Add to dashboard Cite

[1] Teleseismic shear wave splitting measured at 56 continuous and temporary seismographs deployed in a 500 km by 600 km area around the Yellowstone hot spot indicates that fast anisotropy in the mantle is parallel to the direction of plate motion under most of the array. The average split time from all stations of 0.9 s is typical of continental stations. There is little evidence for plume-induced radial strain, suggesting that any contribution of gravitationally spreading plume material is undetectably small with respect to the plate motion velocity. Two stations within Yellowstone have splitting measurements indicating the apparent fast anisotropy direction (f) is nearly perpendicular to plate motion. These stations are $30 km from stations with f parallel to plate motion. The 70°r otation over 30 km suggests a shallow source of anisotropy; however, split times for these stations are more than 2 s. We suggest melt-filled, stress-oriented cracks in the lithosphere are responsible for the anomalous f orientations within Yellowstone. Stations southeast of Yellowstone have measurements of f oriented NNW to WNW at high angles to the plate motion direction. The Archean lithosphere beneath these stations may have significant anisotropy capable of producing the observed splitting.

show abstract

“…Larger earthquakes of M > 6.5 have not occurred within the caldera in historic times, suggesting that the stresses there are not sufficient to produce a large event perhaps because of the limited thickness of the brittle layer of 4 km to 6 km, owing to high temperatures. A pronounced lowvelocity upper crustal body in the northeast caldera exhibits a P wave velocity of ~4.8 km/s, which is a 20% reduction [Daniel and Boore, 1982], and joint inversion of teleseismic unusual upper crustal environment and have been modeled delays and long-wavelength gravity anomalies [Evoy, 1977], through a range of compositions and state from a pervasive indicate that low Vp velocities, reduced up to 15%, and a Vs steam-or gas-filled zone to a body of unusual silicic reduction of up to 30% are coincident with a 10% density composition, to an end-member silicic or mafic body with up decease to depths of -150 km beneath the Yellowstone to a 30% partial melt [Iyer et al, 1981;Lehman et al, 1982; Plateau. These investigations revealed a heterogeneous upper crest (Figure 3) where the Pg velocities are reduced by 10% to 5.4 km/s beneath the Yellowstone caldera compared to the thermally unaffected upper crust of the surrounding Rocky Mountains with 6.0 km/s P g velocities [Brokaw, 1985].…”

mentioning

confidence: 99%

“…The technique is similar to teleseismic and local earthquake travel time inversion techniques that have been employed in studies of geothermal systems [Evoy, 1977;Iyer et al 1981;Benz and Smith, 1984;Kissling, 1987;Evans and Zucca, 1988]. The technique is similar to teleseismic and local earthquake travel time inversion techniques that have been employed in studies of geothermal systems [Evoy, 1977;Iyer et al 1981;Benz and Smith, 1984;Kissling, 1987;Evans and Zucca, 1988].…”

mentioning

confidence: 99%

P wave attenuation of the Yellowstone Caldera from three‐dimensional inversion of spectral decay using explosion source seismic data

Clawson¹,

Smith²,

Benz³

1989

J. Geophys. Res.

View full text Add to dashboard Cite

Using explosion source, seismic refraction data, recorded in the 1978 and 1980 Yellowstone‐Snake River Plain seismic experiments, a three‐dimensional inversion of differential P wave attenuation was used to assess the relative variations in Q−1 in and around the volcanically active, 45 km by 70 km, Yellowstone caldera, northwestern Wyoming. Differential attenuation was derived from spectral decay of upper crustal Pg phases, observed from six explosions and recorded at 90 temporary stations. Because of the relatively short time windows used to determine the spectral content, a maximum entropy technique was employed to estimate the spectra that yielded an optimally small variance. Differential P wave attenuation was calculated from least squares determinations of the spectral ratios corrected for source and path effects. The observed differential attenuation parameters were then inverted using a weighted least squares technique for a discretized, 70×105 km, three‐dimensional surface and upper crustal Q−1 model of the Yellowstone caldera and surrounding region. Results showed that the surface layer, to depths of 2 km within the Yellowstone caldera, is characterized by relatively high attenuation with low Q values less than 30, compared to values of 38 to 50 outside the caldera. The higher attenuation in the caldera's surface layer is thought to be associated with Quaternary lake sediments, highly altered rhyolites, and the possible influence of steam in areas of hydrothermal activity. In the crystalline upper crust, at depths of 2 km to 12 km, Q values of 40 to 70 were observed in areas of thick sedimentary fill northwest of the caldera and in areas of hydrothermal activity. Within the caldera, upper crustal attenuation generally corresponded to Q of 200 in areas that are interpreted to be associated with hot but now solidified granitic material. In comparison, relatively high attenuation, Q = 40, was observed in the upper crust of the northeastern Yellowstone caldera in an area that also corresponds to a 20% reduction in Pg velocity, a prominent negative Bouguer gravity low of −20 mGal, near Yellowstone's largest area of hydrothermal activity and near a Quaternary, volcanic resurgent dome. On the basis of constitutive models of velocity and density, this zone of high attenuation is likely a product of unusual hydrothermal activity, highly altered upper‐crustal rocks, a shallow magmatic source or a highly porous, steam‐saturated body. Outside the caldera, the upper crust is relatively unaffected by high temperatures and thermal alteration, and the corresponding attenuation is low with Q values greater than 200.

show abstract

A deep low-velocity body under the Yellowstone caldera, Wyoming: Delineation using teleseismic P-wave residuals and tectonic interpretation

Cited by 42 publications

References 13 publications

P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography

P-wave velocity structure of the uppermost mantle beneath Hawaii from traveltime tomography

Models of lithosphere and asthenosphere anisotropic structure of the Yellowstone hot spot from shear wave splitting

P wave attenuation of the Yellowstone Caldera from three‐dimensional inversion of spectral decay using explosion source seismic data

Contact Info

Product

Resources

About