High-resolution images of the lower crust: deep seismic reflections from 15 to 180 Hz

Warner, Michael; Spaargaren, B.; Jones, Rob; Watts, Doyle R.; Doody, J. J.

doi:10.1016/0040-1951(94)90086-8

Cited by 12 publications

(4 citation statements)

References 12 publications

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“…An earthquake will contain length scales spanning many orders of magnitudes, from the grain‐size scale to total fault length. Length scales of juxtaposed rock units are on the order of 10 2 –10 5 m [ Warner et al , 1994; Holliger and Levander , 1992]. Geometric irregularities (fault bends, jogs, offsets) occur at lengths scales of 10 2 –10 4 m and smaller.…”

Section: Discussionmentioning

confidence: 99%

A spatial random field model to characterize complexity in earthquake slip

2002

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[1] Finite-fault source inversions reveal the spatial complexity of earthquake slip over the fault plane. We develop a stochastic characterization of earthquake slip complexity, based on published finite-source rupture models, in which we model the distribution of slip as a spatial random field. The model most consistent with the data follows a von Karman autocorrelation function (ACF) for which the correlation lengths a increase with source dimension. For earthquakes with large fault aspect ratios, we observe substantial differences of the correlation length in the along-strike (a x ) and downdip (a z ) directions. Increasing correlation length with increasing magnitude can be understood using concepts of dynamic rupture propagation. The power spectrum of the slip distribution can also be well described with a power law decay (i.e., a fractal distribution) in which the fractal dimension D remains scale invariant, with a median value D = 2.29 ± 0.23, while the corner wave number k c , which is inversely proportional to source size, decreases with earthquake magnitude, accounting for larger ''slip patches'' for large-magnitude events. Our stochastic slip model can be used to generate realizations of scenario earthquakes for near-source ground motion simulations.INDEX TERMS: 7209 Seismology: Earthquake dynamics and mechanics; 7215 Seismology: Earthquake parameters; KEYWORDS: earthquake source characterization, complexity of earthquake slip, spatial random fields, correlation length of asperities growing with earthquake magnitude, earthquake rupture dynamics, strong ground motion simulation Citation: Mai, P. M., and G. C. Beroza, A spatial random field model to characterize complexity in earthquake slip,

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Section: Discussionmentioning

confidence: 99%

A spatial random field model to characterize complexity in earthquake slip

2002

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“…One of the highest frequency images ever acquired of the crust-mantle transition was obtained also under the Caledonides. Warner et al (1994) used explosive and deeply buried sensors, this acquisition designed allowed recording signal characterized by frequencies over 100 Hz. The images provide evidence of a highly structured Moho transition, at least in the southern UK Warner et al (1994).…”

Section: The Moho Under Paleozoic Mountain Orogens 511 From the Apmentioning

confidence: 99%

The Mohorovičić discontinuity beneath the continental crust: An overview of seismic constraints

2013

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The seismic signature of the Moho from which geologic and tectonic evolution hypothesis are derived are to a large degree a result of the seismic methodology which has been used to obtain the image. Seismic data of different types, passive source (earthquake) broad-band recordings, and controlled source seismic refraction, densely recorded wide-angle deep seismic reflection, and normal incidence reflection (using VibroseisTM, explosives, or airguns), have contributed to the description of the Moho as a relatively complex transition zone. Of critical importance for the quality and resolution of the seismic image are the acquisition parameters, used in the imaging experiments. A variety of signatures have been obtained for the Moho at different scales generally dependent upon bandwidth of the seismic source. This variety prevents the development of a single universally applicable interpretation. In this way source frequency content, and source and sensor spacing determine the vertical and lateral resolution of the images, respectively. In most cases the different seismic probes provide complementary data that gives a fuller picture of the physical structure of the Moho, and its relationship to a petrologic crust-mantle transition. In regional seismic studies carried out using passive source recordings the Moho is a relatively well defined structure with marked lateral continuity. The characteristics of this boundary change depending on the geology and tectonic evolution of the targeted area. Refraction and wide-angle studies suggest the Moho to be often a relatively sharp velocity contrast, whereas the Moho in coincident high-quality seismic reflection images is often seen as the abrupt downward decrease in seismic reflectivity. The origin of the Moho and its relation to the

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“…The bottom of the continuous band can often be interpreted as the Moho. For example, in the COCORP data [29] and a conventional deep seismic reflection survey in England [30], they interpreted Moho as the bottom of the layered reflections. In addition， amplitude of the reflection events are also necessary to decide Moho.…”

Section: Resultsmentioning

confidence: 99%

Variation of Moho Depth across Bangong-Nujiang Suture in Central Tibet—Results from Deep Seismic Reflection Data

Lu¹,

Gao²,

Li³

et al. 2015

IJG

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There is a long-term dispute at Moho depth across the Bangong-Nujiang suture (BNS). Due to the complicated and changeable seismic geological condition, it is not easy to acquire images of the reflective Moho in central Tibet. In the support of the SinoProbe project, a series of deep seismic reflection profiles were conducted to image Moho structure across the BNS and the Qiangtang terrane. These profiles extend from the northern Lhasa terrane to the Qiangtang terrane crossing the BNS. Both shot gathers and migration data show clear Moho images beneath the BNS. The Moho depth varies from 75.1 km (~24 s TWT) beneath the northmost Lhasa terrane to 68.9 km (~22 s TWT) beneath southmost Qiangtang terrane, and rises smoothly to 62.6 km (~20 s TWT) at ~28 km north of the BNS beneath the Qiangtang terrane. We speculate that the Moho appears a 6.2 km sharp offset across the BNS and becomes ~12.5 km shallower from the northmost Lhasa terrane to the south Qiangtang terrane at ~28 km north of the BNS. The viewpoint of Moho depth across the BNS based on deep seismic reflection data is inconsistent with the previous 20 km offset.

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High-resolution images of the lower crust: deep seismic reflections from 15 to 180 Hz

Cited by 12 publications

References 12 publications

A spatial random field model to characterize complexity in earthquake slip

A spatial random field model to characterize complexity in earthquake slip

The Mohorovičić discontinuity beneath the continental crust: An overview of seismic constraints

Variation of Moho Depth across Bangong-Nujiang Suture in Central Tibet—Results from Deep Seismic Reflection Data

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