PRISM - Probabilistic Inference of Source Mechanisms

我们有限的地震知识对整个地震学工作有多大影响？该项目旨在量化有关地震的知识限度，即震源。它的目的是使用贝叶斯推理对全球中等规模地震(里氏5.5级)的震源解的不确定性进行严格估计。结果将以全球概率地震目录的形式与地球科学界共享。由于地震在几乎所有固体地球科学中都被用来推断系统地球的性质，震源解的不确定性传播到许多其他学科。在这种情况下，地震被直接用来限制一个地区的构造体制，但也间接地用于地震层析成像，在地震层析成像中，地震被用作强大的声源来成像地球深处。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。这将促进关于破裂大小和持续时间尺度的研究，从而促进对断层破裂传播性质的研究。包括震源参数不确定性的开放数据集将对其他一系列领域产生影响，例如地震危险图或构造解释。作为主要应用，应说明震源不确定性对地震层析成像的影响。这种方法受到震源参数不确定性的强烈阻碍。震源不确定性对这些结果的影响到目前为止是未知的，应予以量化。为此，将使用两个频率相关的旅行时间数据集(欧洲和北美)和波形层析成像方法。此外，国际合作者将使用目录来确定不确定因素对应力降参数的影响。在项目期间和之后，将向整个地球科学界提供所产生的目录。

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.