Geometrical spreading function for short-period S and coda waves recorded in southern Spain

Ibáñez, Jesús M.; Pezzo, E. Del; Alguacil, Gerardo; Miguel, F. De; Morales, J.; Martino, Salvatore; Sabbarese, C.; Posadas, A. M.

doi:10.1016/0031-9201(93)90070-p

Cited by 12 publications

(7 citation statements)

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“…Therefore, inferred Q anomalies take implicitly into account the multiplicity of such effects. Similar observations were carried out by several authors such as Ibáñez et al (1993), Akinci et al (1995a) and Akinci et al (1995b). These authors point out that the geometrical spreading and quality factor Q are strongly coupled, in the sense that the estimate of Q depends on c and vice versa.…”

Section: P-wave Attenuation Tomography With the Coda Normalization Mesupporting

confidence: 65%

“…These authors point out that the geometrical spreading and quality factor Q are strongly coupled, in the sense that the estimate of Q depends on c and vice versa. Direct measurements of the geometrical spreading factor show that c depends on the density of heterogeneities (Ibáñez et al 1993), possibly affecting the scattering Q estimate rather than the intrinsic Q (e.g., Akinci et al 1995a).…”

Section: P-wave Attenuation Tomography With the Coda Normalization Mementioning

confidence: 99%

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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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Section: P-wave Attenuation Tomography With the Coda Normalization Mesupporting

confidence: 65%

Section: P-wave Attenuation Tomography With the Coda Normalization Mementioning

confidence: 99%

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

et al. 2015

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“…However, other studies have found a higher value of β. Ibáñez et al (1993) found a value of β 1:2 using coda waves independently of determining coda Q. For Lg waves, Akinci et al (1995) found β values between 0.5 and 0.9 by inverting their data set for Q and β simultaneously.…”

Section: The Geometrical Spreading Parameter βmentioning

confidence: 99%

CodaQin Different Tectonic Areas, Influence of Processing Parameters

Havskov¹,

Sørensen²,

Vales³

et al. 2016

Bulletin of the Seismological Society of America

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Published results of coda Q show a large variation in values. These variations are often claimed to be related to different tectonics, whereas they might just be related to using different assumptions in the processing, leading to different input parameters for the analysis. In this study, the effect of using different processing parameters is investigated and significant differences, particularly at low frequencies, are observed. We find a new set of optimal parameters, which we recommend using in future studies. Using a short lapse time of 30 s and optimal parameters, data from both similar and very different tectonic regions are used to calculate coda Q using the same program and the same parameters.

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“…Some studies of body wave attenuation shows that the coefficient b associated with the geometrical spreading is more complex than b = 1 and they attribute this to complex velocity structures (Ibáñez et al, 1993 ; Olafsson et al ., 1998 ; Castro et al ., 1999 ; Akıncı et al ., 2006 ; Padhy, 2009 ). Ou and Herrmann ( 1990 ) found that G(r) may depend upon source depth in layered structures, while Burger et al, ( 1987 ) remarked the importance of post-critical reflections from mid-lower crustal velocity discontinuities and the Moho in controlling amplitudes in certain distance ranges.…”

Section: Resultsmentioning

confidence: 99%

S-wave attenuation in northeastern Sonora, Mexico, near the faults that ruptured during the earthquake of 3 May 1887 Mw 7.5

Villalobos-Escobar

Castro

2014

SpringerPlus

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We used a new data set of relocated earthquakes recorded by the Seismic Network of Northeastern Sonora, Mexico (RESNES) to characterize the attenuation of S-waves in the fault zone of the 1887 Sonora earthquake (Mw 7.5). We determined spectral attenuation functions for hypocentral distances (r) between 10 and 140 km using a nonparametric approach and found that in this fault zone the spectral amplitudes decay slower with distance at low frequencies (f < 4 Hz) compared to those reported in previous studies in the region using more distant recordings. The attenuation functions obtained for 23 frequencies (0.4 ≤ f ≤ 63.1 Hz) permit us estimating the average quality factor QS = (141 ± 1.1 )f(0.74 ± 0.04) and a geometrical spreading term G(r) = 1/r0.21. The values of Q estimated for S-wave paths traveling along the fault system that rupture during the 1887 event, in the north–south direction, are considerably lower than the average Q estimated using source-station paths from multiple stations and directions. These results indicate that near the fault zone S waves attenuate considerably more than at regional scale, particularly at low frequencies. This may be the result of strong scattering near the faults due to the fractured upper crust and higher intrinsic attenuation due to stress concentration near the faults.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-3-747) contains supplementary material, which is available to authorized users.

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Geometrical spreading function for short-period S and coda waves recorded in southern Spain

Cited by 12 publications

References 20 publications

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

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

CodaQin Different Tectonic Areas, Influence of Processing Parameters

S-wave attenuation in northeastern Sonora, Mexico, near the faults that ruptured during the earthquake of 3 May 1887 Mw 7.5

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