PRISM - Probabilistic Inference of Source Mechanisms

我们对地震的有限知识对整个地震学的影响有多大？该项目旨在量化有关地震的知识的局限性，地震源。它旨在使用贝叶斯推断对全球中等规模地震（震级> 5.5）的震源解的不确定性进行严格估计。研究结果将以全球概率地震目录的形式与地球科学界分享，由于几乎所有固体地球科学都用地震来推断地球系统的性质，震源解的不确定性也传播到许多其他学科。在这种情况下，地震被直接用于限制一个地区的构造状态，但也被间接地用于地震层析成像，地震被用作强大的声源，以成像地球内部深处。与现有目录相比，PRISM将包含概率密度函数形式的结果以及对地震时间演化的估计，即所谓的震源时间函数。这将促进对破裂大小和持续时间的标度的研究，从而促进对断层破裂传播性质的研究。一个包含震源参数不确定性的开放数据集将对一系列其他领域产生影响，如地震危险性绘图或构造解释。作为主要应用，应显示震源不确定性对地震层析成像的影响。这种方法受到源参数不确定性的严重阻碍。源不确定性对这些结果的影响是迄今未知的，应予以量化。为此，两个频率相关的旅行时间数据集（欧洲和北方美洲）将与波形层析成像的方法。此外，国际合作者将使用该目录来确定不确定性对应力降等参数的影响。在项目期间和之后，将向整个地球科学界提供由此产生的目录。

How much does our limited knowledge about earthquakes affect the whole seismological effort? This project aims at quantifying the limits of knowledge about earthquakes, the seismic sources. It aims at rigorously estimating the uncertainty of seismic source solutions using Bayesian Inference for intermediate size earthquakes (magnitude > 5.5) globally. The results will be shared with the geoscientific community in form of a global probabilistic earthquake catalogue.Since earthquakes are used to infer properties of the system earth in almost all solid earth geosciences, the uncertainty of source solutions propagates into many other disciplines. This is the case, where earthquakes are used directly, e.g. to constrain the tectonic regime of a region, but also indirectly, as in seismic tomography, where earthquakes are used as powerful sound sources to image the deep interior of the Earth. Compared to existing catalogues, PRISM will contain results in form of probability density functions as well as an estimate of the temporal evolution of the earthquake, the so-called Source Time Function. This will foster research about scaling of rupture size and duration and thereby the nature of fault rupture propagation. An open dataset including uncertainties of source parameters will have an effect on a range of other fields, such as seismic hazard mapping or tectonic interpretation. As a primary application, the influence of source uncertainty on seismic tomography shall be shown. This method that is strongly hindered by uncertainty in the source parameters. The effect of source uncertainties on these results was hitherto unknown and shall be quantified. To this end, two frequency-dependent travel-time datasets (Europe and Northern America) will be used with the method of waveform tomography. Additionally, international cooperators will use the catalogue to determine the effect of uncertainties on parameters as the stress drop. During and after the project, the resulting catalogue will be available for the whole geoscientific community.