NSFGEO-NERC: The central Apennines earthquake cascade under a new microscope

在两个多月的时间里，沿着亚平宁山脉中部50公里的震源区发生了三次M&GT；5.9级强烈地震。首先，8月24日发生的6.0级地震造成297人死亡，阿马特里切、阿库莫利和佩斯卡拉·迪·特隆托等中世纪村庄被摧毁。10月26日，两次5.4级和5.9级大地震(32分钟后)在1997年科尔菲奥里托6.0级地震所在的同一地区向北更远的30公里处发生。迄今最大的(M=6.5)事件仅在四天后，即10月30日发生，对Norcia的建筑物造成严重破坏，包括历史悠久的圣贝内代托大教堂。该地区在历史和现代都曾发生过规模巨大的破坏性地震。这是第三个发生在亚平宁中部的灾变序列，之前的序列分别在1997年和2009年在北部(M=6.0Colfiorito)和南部(M=6.1 L‘Aquila)。文化遗产遗址，包括阿马特里切村附近举世闻名的中世纪教堂，在许多情况下遭到严重破坏和完全坍塌。在这种灾后环境下，显然需要提高我们对这种序列演变背后的理解，并开发工具，以支持未来明智的决策。我们的研究将基于一个独特的高质量数据集，这是英国和意大利正在进行的合作的产物，自去年秋天以来，英国和意大利在受影响地区部署了超过85个地震传感器。这一史无前例的观测能力使我们能够捕捉导致序列内大事件的地震活动的“广度和深度”。基于这个数据集，我们将开发创新的方法，将测量结果转换为基本过程的可测试物理模型。我们的目标是开发一个全面的地震目录，其中包括准确的位置、震源参数和震源机制，这些机制来自能够检测、定位和表征即使是最小的事件的算法。这个新的‘显微镜’提供了对解开意大利2016年阿马特里切/诺西亚延长地震等序列背后的物理过程至关重要的信息。然后，我们将使用高精度目录来制定和测试替代地震触发假设，并将这些假设整合到使用经验和物理模型的可测试预测模型的开发和验证中，以确保高可预测性。该项目汇集了来自美国、英国和意大利的地震探测、震源特征、地震触发和预测方面的世界专家，努力开发突破性的方法来应对当前的挑战，这些挑战不仅阻碍了我们对地震过程背后的理解，还削弱了我们在任何震后灾难环境中的科学反应。在我们的研究过程中，我们将进一步参与国际倡议，如CSEP(地震可预测性研究合作实验室)，以确保对我们的预测模型进行透明测试，以及EPOS(欧洲板块观测系统)，以最大限度地促进知识交流和该项目在其他国家的科学影响。新的观测能力可以在几个小时内探测、定位和表征即使是最小的震级事件，这一能力将适用于美国和欧洲的诱发、地热和火山活动地区。我们预计，我们的研究框架的应用，特别是在世界各地地震高风险地点的应用，将使未来能够在不同的操作和文化环境中以相同的科学标准做出决策。

Three strongly felt earthquakes of magnitude M>5.9 occurred within a 50 km source zone along the Central Apennines mountain chain in a period of just over 2 months. The first, on the 24th August M=6.0 earthquake killed 297 people, leaving the medieval villages of Amatrice, Accumoli and Pescara di Tronto devastated. On 26th October two large shocks of M=5.4 and M=5.9 (32 minutes after) struck ~30 km further north in the same region as the 1997 M=6.0 Colfiorito earthquake. The largest (M=6.5) event to date that occurred only four days later, on 30th October, caused severe damage to buildings at Norcia, including the historical cathedral of San Benedetto. The area has been struck by destructive earthquakes of significant magnitude in historical and modern times. This is the third catastrophic sequence to occur in the Central Apennines, with preceding sequences to the north (M=6.0 Colfiorito) and south (M=6.1 L'Aquila) in 1997 and 2009, respectively. Cultural heritage sites including word-famous medieval churches near Amatrice village, have suffered severe damage and total collapse in many cases.Within this post-disaster environment there is a clear need to improve our understanding behind the evolution of such sequences and to develop tools that can support informed decision-making in the future. Our research will be based on a unique high quality dataset that is a product of on-going UK-Italian collaboration involving the deployment of more than 85 seismic sensors at the affected area since last fall. This unprecedented observational capability enables us to capture the "breadth and depth" of seismicity leading to the large events within the sequence. Based on this dataset we will develop innovative methods to translate measurements into testable physical models for the underlying processes. We aim at developing a comprehensive earthquake catalog that includes precise locations, source parameters and focal mechanisms derived from algorithms that are able detect, locate and characterize even the smallest events. This new 'microscope' provides information that is crucial for unravelling the physical processes that underlie sequences such as the extended 2016 Amatrice/Norcia earthquakes in Italy. We will then use the high-accuracy catalog to formulate and test alternative earthquake triggering hypotheses and integrate those in the development and validation of testable forecast models using empirical and physics based models to ensure high predictability. The project brings together world-experts on earthquake detection, seismic source characterization, earthquake triggering and forecasting from US, UK and Italy in an effort to develop breakthrough approaches to address current challenges that not only impede our understanding behind earthquake processes but also weaken our scientific response in any post-earthquake disaster environment. In the course of our research we will involve further international initiatives such as CSEP (Collaboratory for the Study of Earthquake Predictability) to ensure transparent testing of our forecast models, and EPOS (European Plate Observation System) to maximize knowledge exchange and the scientific impact of the project in other countries. The new observational capability to detect, locate and characterize even the smallest magnitude events within few hours will find application to induced, geothermal and volcanic activity areas in US and Europe. We anticipate that the application of our research framework especially in high seismic hazard sites worldwide will enable future decision making with the same scientific standards across different operational and cultural environments.