Spatial distribution of intrinsic and scattering seismic attenuation in active volcanic islands – II: Deception Island images

Prudencio, Janire; Ibáñez, Jesús M.; García-Yeguas, Araceli; Pezzo, Edoardo Del; Posadas, A. M.

doi:10.1093/gji/ggt360

Cited by 37 publications

(56 citation statements)

References 35 publications

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“…Within the frequency range 3-18 Hz, a value of 250 m is obtained for on-volcano stations and 430 m for off volcano. 250 m is comparable with typical values of between 100 m and 1000 m found at other volcanic sites [8,9,[38][39][40][41][42] where scattering effects have been observed to dominate over intrinsic attenuation. However, away from the strongly scattering regime close to a volcano, typical crustal values are in the range of 100 km and so 430 m for off-volcano stations is several orders of magnitude lower than it should be.…”

Section: Diffusionsupporting

confidence: 83%

Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA

et al. 2017

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Abstract:We present an expanded approach of the diffusive approximation to map strongly scattering geological structures in volcanic environments using seismic coda intensities and a diffusive approximation. Seismic data from a remarkably consistent hydrothermal source of Long-Period (LP) earthquakes, that was active during the late 2004 portion of the 2004-2008 dome building eruption of Mount St. Helens Volcano, are used to obtain coefficient values for diffusion and attenuation, and describe the rate at which seismic energy radiates into the surrounding medium. The results are then spatially plotted as a function of near-receiver geology to generate maps of near-surface geological and geophysical features. They indicate that the diffusion coefficient is a marker of the near-receiver geology, while the attenuation coefficients are sensitive to deeper volcanic structures. As previously observed by other studies, two main scattering regimes affect the coda envelopes: a diffusive, multiple-scattering regime close to the volcanic edifice and a much weaker, single-to-multiple scattering regime at higher source-receiver offsets. Within the diffusive, multiple-scattering regime, the spatial variations of the diffusion coefficient are sufficiently robust to show the features of laterally-extended, coherent, shallow geological structures.

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Section: Diffusionsupporting

confidence: 83%

Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA

et al. 2017

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“…In another sense, Prudencio et al (2015) confirmed the effects of unconsolidated materials, hydrothermal system and partial melt rocks under Deception Island on the pattern of attenuation. In addition, in the same volcano, the contrast of the crystalline basement and volcanic structure observed by Zandomeneghi et al (2009) is more clearly detected when separation of intrinsic and scattering attenuation is obtained (Prudencio et al 2013b). These observations done in Deception volcano caldera are very close to others performed in a very similar volcano, but located in an opposite region (Alaska against Antarctica), as those made in Okmok volcano (Ohlendorf et al 2014).…”

Section: Introductionmentioning

confidence: 88%

3D Attenuation Tomography of the Volcanic Island of Tenerife (Canary Islands)

et al. 2015

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This paper shows a new multidisciplinary interpretation approach to the internal structure of Tenerife Island. The central core of this work is the determination of the three-dimensional attenuation structure of the region using P-waves and the coda normalization method. This study has been performed using 45,303 seismograms recorded at 85 seismic stations from an active experiment (air gun shots) conducted in January 2007. The interpretation of these new results is done combining the new images with previous studies performed in the area such as seismic velocity tomography, magnetic structure, magnetotelluric surveys or gravimetric models. Our new 3D images indicate the presence of seismic attenuation contrasts, with areas of high and low seismic attenuation patterns. High seismic attenuation zones are observed both in shallow and in deeper areas. The shallowest area of Las Cañadas caldera complex (1-3 km thick) is dominated by high attenuation behavior, and it is interpreted as the combined effect of sedimentary and volcanoclastic deposits, multifracture systems and the presence of shallow aquifers. At the same time, the deeper analyzed area, more than 8 km below sea level, is dominated by a high attenuation pattern, and it is interpreted as the consequence of the effect of hightemperature rocks in the crustal-mantle boundary. This interpretation is compatible and confirmed by previous models that indicate the presence of underplating magma in this region. On the contrary, some low attenuation bodies and structures have been identified at different depths. A deep low attenuation central body is interpreted as the original central structure associated with the early stage of Tenerife Island. At shallower depths, some low attenuation bodies are compatible with old intermediate magmatic chambers postulated by petrological studies. Finally, in the north of the island (La Orotava valley) we can interpret the low attenuation structure as the headwall of this valley, supporting the idea that Las Cañadas caldera and this valley resulted from two different destructive processes.

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“…They do interpret these results as produced by a zone of strong heterogeneity, as done in most volcanic areas (Del Pezzo 2008), where the presence of magma patches cannot be excluded. Recently, Prudencio et al (2013) obtained the regional 2D distribution of intrinsic and scattering attenuation of the Island by using the same waveform dataset employed to image its velocity structure and the diffusion model. The authors confirm the presence of a high scattering attenuation body below the inner bay of Deception Island, strongly interacting with the coda wave field, and which may be compatible with the existence of magma.…”

Section: Seismic Attenuation Observationsmentioning

confidence: 99%

“…The stations record waveforms with excellent signal-to-noise ratios (larger than 10) for the entire signal above 8 Hz only. However, both Vila et al (1995) and Prudencio et al (2013) show abnormally low attenuation values at high frequencies in the Port Foster bay, where we focus our attention. Due to this strong attenuation, we cannot provide reliable attenuation models of structures as deep as 4 km at frequencies larger than 10 Hz.…”

Section: Data and Ray Tracingmentioning

confidence: 99%

“…There are many results that help us better understand the dynamic and volcanological framework of the area, such as Vila et al (1992), , Ibáñez et al (1997Ibáñez et al ( , 2000Ibáñez et al ( , 2003, Saccorotti et al (2001), Martinez-Arevalo et al (2003), Benitez et al (2007), Carmona et al (2010Carmona et al ( , 2012Carmona et al ( , 2014, and García-Yeguas et al (2010). One of the objectives of these seismic studies is to provide 2D or 3D structure of the area, by using active or passive data as has been done by Ben-Zvi et al (2009), Zandomeneghi et al (2009), and Prudencio et al (2013). These seismic models have been used to confirm or help to build other geophysical or geodynamic models of the island, such as magnetotelluric (Pedrera et al 2012), geomagnetic (Muñoz Martín et al 2005, gravimetric (Catalan et al 2006), or geodetic Prates et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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The 3D Attenuation Structure of Deception Island (Antarctica)

et al. 2015

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The seismic and volcanological structure of Deception Island (Antarctica) is an intense focus topic in Volcano Geophysics. The interpretations given by scientists on the origin, nature, and location of the structures buried under the island strongly diverge. We present a high-resolution 3D P-wave attenuation tomography model obtained by using the coda normalization method on 20,293 high-quality waveforms produced by active sources. The checkerboard and synthetic anomaly tests guarantee the reproduction of the input anomalies under the island down to a depth of 4 km. The results, once compared with our current knowledge on the geological, geochemical, and geophysical structure of the region, depict Deception as a piecemeal caldera structure coming out of the Bransfield Trough. Highattenuation anomalies contouring the northeastern emerged caldera rim correlate with the locations of sediments. In our interpretation, the main attenuation contrast, which appears under the collapsed southeastern caldera rim, is related to the deeper feeding systems. A unique P-wave high-attenuation spherical-like anomaly in the inner bay extends between depths of 1 and 3 km. The northern contour of the anomaly coincides with the calderic rim both at 1 and 2 km, while smaller anomalies connect it with deeper structures below 3 km, dipping toward the Bransfield Trough. In our interpretation, the large upper anomaly is caused by a high-temperature shallow (1-3 km deep) geothermal system, located beneath the sediment-filled bay in the collapsed blocks and heated by smaller, deeper contributions of molten materials (magma) rising from southeast.

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Spatial distribution of intrinsic and scattering seismic attenuation in active volcanic islands – II: Deception Island images

Cited by 37 publications

References 35 publications

Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA

Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA

3D Attenuation Tomography of the Volcanic Island of Tenerife (Canary Islands)

The 3D Attenuation Structure of Deception Island (Antarctica)

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