Innovative seismological analysis for the study of tectonic structures and natural hazards

地震学分析是研究构造和自然灾害(如大地震和山体滑坡)的重要工具。在加拿大，地震台站的密度和分布在不同地区之间差异很大，许多地方没有得到充分的覆盖。由于在全国范围内加密地震台网是不现实的，而且成本也不高，因此，在地震学分析中采取创新的方法成为提高数据分辨率的最实用和最有效的途径。在这个提案中，我们计划开发新的算法来解决大多数传统方法将失败的各种具有挑战性的问题。首先，我们将在成功的震源扫描算法的基础上，设计一种新的方法来精确定位震源，而不需要拾相和不同台站相同震相的正确关联。这种新方法将包括来自瞬时粒子运动、多个相位和波形幅度的额外信息，从而更加有效和准确。其次，我们将开发一种混合方法，以最高分辨率成像地震速度结构。我们计划结合环境地震噪声相关性和地震的约束，而不是使用同类数据类型进行地震层析成像。其他混合方法包括使用来自海底地震仪和近海地区陆基台站的数据，以及使用来自区域网络和密集阵列的数据。最后，我们计划设计一种有效的网格矩-张量反演方法来研究北冰洋等偏远地区的幕式震动和滑动(ETS)事件的震源特征。申请的资金完全用于支持研究生在维多利亚大学和加拿大地质调查局之间的合作框架下开展拟议的研究活动。

Seismological analysis is a critical tool in the study of tectonics and natural hazards (e.g., major earthquakes and landslides). In Canada, the density and distribution of seismograph stations vary dramatically from one region to another with many places insufficiently covered. Since a country-wide densification of seismic network is unrealistic and cost prohibited, taking an innovative approach in seismological analysis becomes the most practical and effective way to enhance data resolution. In this proposal, we plan to develop new algorithms to address a variety of challenging problems that most traditional methods would fail. First, we will design a new methodology, based on the successful Source-Scanning Algorithm, to precisely locate seismic sources without the necessity of phase picking and correct association of the same phases at different stations. This new method will include extra information from instantaneous particle motions, multiple phases, and waveform amplitudes to be more efficient and accurate. Second, we will develop a hybrid approach to image seismic velocity structures at the highest resolution. Instead of conducting seismic tomography using a homogeneous data type, we plan to combine constraints from both ambient seismic noise correlation and earthquakes. Other hybrid approaches include using data from both ocean-bottom-seismographs and land-based stations for offshore regions, and using data from both regional networks and dense arrays. Finally, we plan to design an efficient grid moment-tensor inversion method to study the source characteristics of episodic tremor and slip (ETS) events and earthquakes in remote regions such as the Arctic North. The requested funding is exclusively for the support of graduate students to conduct the proposed research activities under the collaboration framework between the University of Victoria and Geological Survey of Canada.