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

Abstract

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

The nature of the Moho in Australia from reflection profiling: A review

“…[4,8]). In this work we use a classification based on the nature of the reflectivity at the base of the crust and its visibility in the seismic records:…”

“…Reflection work in Australia's Gondwana neighbour India [7] has concentrated on Proterozoic suture zones. Fine examples of reflection results from a wide range of geologic environments are provided by Carbonnell et al [8], who also discuss the way in which refraction and receiver function analysis can be used to build up a more coherent picture of the many different styles of transition between crust and mantle in the continents.…”

A New Seismic Data Set on the Depth of the Moho in the Alps

“…To a large extent, the resolution and imaging depth depend on the frequency content of the employed seismic source (e.g., low-energy, high-frequency CSS data vs. high-energy, low-frequency earthquake data). It is important to recognize that the knowledge obtained about the crust-mantle transition strongly depends on the applied techniques and their intrinsic resolution capabilities (CARBONELL et al 2013). Given the existing wealth of CSS data in the Eastern Alps, we aim to add complementary information on crustal structures, in particular the Moho topography, from earthquake data.…”

Using large dynamite shots to image the structure of the Moho from deep seismic reflection experiment between the Sichuan basin and Qinling orogen

“…These acquisition parameters control the resolution of the structure of the Moho. The images have a high dependence on the dynamic characteristics of the source signal (Carbonell et al 2013).…”