Quantifying the variability and migration of active normal faulting during the Late Pleistocene-Holocene using 36Cl cosmogenic nuclide techniques

地球上的大部分地区容易发生破坏性地震。地震是无法预测的，地震发生的多变性使得这种自然灾害很难预测。在人类历史上，有许多断裂带从未发生过地震，虽然这些断裂带确实是活跃的，能够发生大地震事件，但它们往往没有意识到是一种威胁。这在大陆尤其如此，构造板块碰撞产生的应变分布在大片地区和复杂的网络中，可能会相互作用。断层之间的相互作用，以及它们在史前时间尺度上的表现，由于难以测量过去的断层运动而知之甚少。在我的研究员生涯中，我将研究在比人类历史更长的时间尺度上导致地震的脆性断层。在我担任研究员期间，我将致力于测量地震发生在过去数万年中的变化情况。一些科学家提出，断层可能有强烈的地震活动期，并以平静的间隔穿插，我的目标是量化这种情况是否发生在土耳其西部的断层上。我还将制作这种行为的模型，这将有助于理解地震的基本可变性。每次断层发生大地震时，沿着断层线的一部分地面相对于它旁边的地面移动。在伸展断层上，断层面被抬升并保存了数千年。当断层面被抬升时，它暴露在不断轰炸地球表面的宇宙源辐射中。这种高能辐射产生了在地球上找不到的同位素；其结果类似于断层面的晒伤。飞机暴露在宇宙射线下的时间越长，同位素浓度就越高(晒得越黑)。我将测量暴露断层面上的宇宙成因同位素浓度剖面，以确定地震造成的断层暴露历史。我的结果将量化强烈地震活动持续多长时间，它们发生的频率有多高，它们是否发生在网络中的每个故障上，以及网络中的故障是否相对于彼此切换和关闭。我还将把我的数据纳入过错行为模型。许多模型假设地震以规则的间隔发生，但重要的是要对驱动不规则复发的因素进行建模。这些模型还将有助于理解复杂网络中断层之间的物理相互作用。我的研究将对了解当地、土耳其西部和世界各地的地震风险产生影响。在土耳其进行实地考察期间，我将与Hasan Sozbilir教授合作，在当地社区进行一次ShakeOut演习。这种演习已经在全球地震多发地区进行，包括美国和日本(www.shakeout.org)。通过每年进行一次模拟地震，演习通过鼓励参与者通过地震检查表来帮助提高灾害准备，其中包括建立一个具有基本生存物品的地震准备工具包，练习如何在地震中寻找掩护，以及确定事件发生后应该做什么。我的研究的更大影响将通过与科学家和政策制定者交流我的结果，以及努力增加对基本地震行为的新理解来实现。

Much of the Earth is prone to damaging earthquakes. Earthquakes cannot be predicted, and the variability of earthquake occurrence makes this natural hazard difficult to anticipate. There are many fault lines that have not had an earthquake during human history, and whilst these faults are indeed active and capable of having big seismic events, they are often not realised to be a threat. This is particularly true on the continents, where the strain that results from the collision of tectonic plates is distributed such that faults occur over huge areas and in complex networks, which may interact. The interaction of faults, and how they behave on prehistoric timescales, is poorly understood due to difficulties in measuring the past fault motion.During my fellowship, I will investigate the brittle faults that cause earthquakes on timescales longer than human history. During my fellowship, I will aim to measure how earthquake occurrence is variable over the last several tens of thousands of years. Some scientists have suggested that faults may have periods of intense earthquake activity, interspersed in quiet intervals, and I aim to quantify whether this occurs on faults in western Turkey. I will also produce models of this behaviour that will help to understand the fundamental variability of earthquakes.Each time a fault has a large earthquake, a portion of the ground along the fault line is moved relative to the ground next to it. On extensional faults, the fault plane is uplifted and preserved for many thousands of years. As the fault plane is uplifted, it is exposed to the cosmogenic radiation that is constantly bombarding the earth's surface. This high-energy radiation produces isotopes that are otherwise not found on Earth; the result is akin to sunburn of the fault plane. The longer the plane has been exposed to cosmogenic rays, the higher the concentration of isotopes (the darker the tan). I will measure profiles of cosmogenic isotope concentrations on exposed fault planes in order to determine the history of fault exposure due to earthquakes. My results will quantify how long periods of intense seismicity last, how frequently they occur, whether they occur on every fault in a network, and whether faults in the network switch on and off relative to one another. I will also incorporate my data into models of fault behaviour. Many models assume that earthquakes occur in regular intervals, but it is important to model what is driving irregular recurrence. The models will also help to understand the physical interaction between faults in complex networks.My research will have impact on understanding earthquake hazard both locally, in western Turkey, and worldwide. During my fellowship whilst conducting field work in Turkey, I will conduct a ShakeOut drill in local communities, in collaboration with Prof Hasan Sozbilir. This drill is already practised in earthquake prone regions across the globe, including in the USA and Japan (www.shakeout.org). By having a mock earthquake once per year, the drill helps to increase disaster preparedness by encouraging participants to go through an earthquake checklist that includes building an earthquake-ready kit with essential survival items, practicing how to take cover during an earthquake, and determining what to do after the event. The greater impact of my research will be realised by communication of my results with scientists and policy makers alike, and efforts to increase the uptake of new understanding of fundamental earthquake behaviour.