Tectonics in the Western Anatolian Extensional Province from sequence stratigraphic modeling of multichannel seismic data in the Gulf of Kusadasi

这个项目将实现两个目标。该项目的第一部分将创建模拟地层学的软件，地层学是指世界各地沉积盆地中积累的岩层。沉积层或地层的模式取决于海平面、构造和沉积物供应变化的复杂相互作用。该模型将适用于模拟从1万年到数百万年的时间尺度上的地层学，将适用于许多设置，并广泛提供给其他科学家使用。用于这种类型的地层模拟的公开软件非常有限。该项目的第二部分将把新软件包应用于土耳其西部的一个地区。在这个区域，地壳的拉伸导致陆地下沉并积累了沉积物层。土耳其同事绘制的地层图显示，在过去100万年里，由于断层作用，海湾出现了复杂的下沉和隆起模式。在10万年的冰川循环中，海平面的变化前后移动了海岸线，这为解释地层的年龄提供了一个框架。我们将模拟地层学，以确定构造，并有助于评估该地区的地震危险性。最近发生的地震达到了M6级，历史上发生的地震达到了M7级。该项目将为一名年轻的土耳其科学家和一名美国本科生提供培训，提高他们定量模拟地层学和估计构造的能力。库萨达斯湾是西安纳托利亚伸展省地震活动最活跃的地区之一，其活动断裂系统表现为北南向伸展、东西向挤压、NE-SW和NW-SE走滑。高分辨率的土耳其多通道地震数据显示了一个伸展盆地，一个切割该地区的裂谷的海上延伸，以及两个与之呈高角度的隆升带。保存下来的沉积物包含13个地层层序，这些地层层序由递进三角洲和带状斜地形组成，与可追溯到1ma的冰川期旋回有关。层序被不同方位的断层切割，显示出沉降和隆升的关联模式。因此，这些矿床可以用来量化垂直运动和断层偏移，从而约束该地区的构造。这些序列被解释为由于10万年的冰川-上升旋回，为破译该地区的构造和沉积历史提供了一个清晰的时间框架。我们建议使用数值层序地层学模型来再现地层几何形状并量化近1ma的垂直运动。为了进行建模，我们将重写Sequence，这是一个在层序地层时间尺度上进行地层学建模的代码。计算出的沉降量在考虑了拉伸的等静力卸载和沉积物的加载后，将用于估算拉伸量。结果将确定该区域是否正在经历纯粹的拉伸，纯粹的剪切，或两者的混合。随着时间的推移，断层的速率将被估计，并将表明变形是稳定的，是增加的还是减少的。对于了解爱琴海-安纳托利亚地区的复杂构造和更好地评估地震危险性，这种尺度的形变定量估计是必要的。

This project will accomplish two goals. The first part of the project will create software for modeling stratigraphy, the layers of rock that accumulate in sedimentary basins around the world. The patterns of the sedimentary layers, or strata, depend on the complex interplay of changes in sea level, tectonics and the supply of sediments. The model will be appropriate for modeling stratigraphy over time scales of from 10,000 to millions of years, will be applicable to many settings, and made broadly available for use by other scientists. There is very limited publically available software for this type of stratigraphic modeling. The second part of the project will apply the new software package to an area off of western Turkey. This is an area where stretching of the crust is causing the land to sink and accumulate layers of sediment. Mapping of the layers by Turkish colleagues show a complex pattern of both subsidence and uplift of the bay over the last 1 million years due to faulting. Changes in sea level that shifted the coastline back and forth over the 100,000-year glacial cycles provide a framework for interpreting ages of the strata. We will model the stratigraphy to determine the tectonics and contribute to assessing the seismic hazard of this region. It has been subject to recent earthquakes up to M6 and historic earthquakes up to M7. The project will provide training for a young Turkish scientist, and a U.S. undergraduate student, adding to their abilities to quantitatively model stratigraphy and estimate tectonics.The Gulf of Kusadasi is one of the most seismically active regions of the Western Anatolian Extensional Province with active fault systems expressing N-S extension, E-W compression, and NE-SW and NW-SE strike slip. High-resolution Turkish multichannel seismic data image an extensional basin, the offshore extension of a rift cutting the area, and two uplifted zones at high angle to it. The preserved sediments contain thirteen stratigraphic sequences composed of prograding deltas with shingled clinoforms that have been correlated to glacioeustatic cycles going back to 1 Ma. The sequences are cut by faults with varied orientations, and they reveal associated patterns of subsidence and uplift. These deposits can thus be used to quantify the vertical motions and fault offsets, and thereby constrain the tectonics of the region. The sequences, interpreted as due to the 100,000 year glacio-eustatic cycles, provide a clear temporal framework for deciphering the tectonic and sedimentary history of the region. We propose to use a numerical sequence stratigraphic model to reproduce the stratal geometries and quantify the vertical motions over the last 1 Ma. In order to do the modeling, we will rewrite Sequence, a code for modeling stratigraphy at a sequence stratigraphic timescale. The calculated subsidence will be used to estimate the extension, after accounting for isostatic unloading by the extension and loading by the sediments. The results will determine whether the area is undergoing pure extension, pure shear, or a mixture of the two. The rates of faulting through time will be estimated and will indicate if the deformation is steady-state, waxing or waning. Quantitative estimates of deformation at this scale are necessary to understand the complex tectonics of the Aegean-Anatolian region, and to better evaluate the earthquake hazard.