The influence of topographic and lithologic features on horizontal deformations
The influence of topographic and lithologic features on horizontal deformations
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地形和岩性特征对水平变形的影响
DOI：
10.1111/j.1365-246x.2009.04072.x
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发表时间：
2009
影响因子：
2.8
通讯作者：
Kroner
中科院分区：
文献类型：
--
作者：
Gebauer;Kroner
为了确定观测地点周围环境对地震仪记录或倾斜仪或应变仪变形观测的影响，已经进行了许多研究。研究通常包括热、大气、地形和空腔效应以及海洋载荷。最近，这些研究已使用有限元（FE）建模继续并扩展。使用气压变化作为加载信号示例性地研究了其影响。天文台地点因当地环境而异。在此基础上，研究了气压变化对地形和岩性特征的影响。开发的模型反映了车站周围不同的地形：宽阔和狭窄的山谷、山坡和平坦地区。在山脚下，模型中融入了画廊。系统地研究了地形和画廊几何的影响，例如：观测地点上方的岩石覆盖率、山坡变化、山谷宽度和岩性。变形仅由气压变化引起，与前进的压力前沿导致的重力变化无关。为了加载，使用均匀载荷和在模型上沿不同方向移动的压力前沿来模拟不同的气压场景。由于考虑了弹性流变学，因此可以将影响缩放到实际发生的气压变化。最初的研究集中在空腔效应上，以估计数量级，以将纯空腔效应与其他影响分开。地形影响的研究，例如对于 PREM 参数化模型，对于 1 hPa 的均匀气压载荷，增加的倾斜角度会导致应变分量非线性增加，幅度高达 2 nstrain，倾斜变化高达 2 nrad。不同的岩性可能会导致五倍大的变形。对于移动的高压区域，会出现高达 2 nstrain 的应变变化和高达 4.2 nrad 的倾斜变化。获得的结果改进了对基本地球动力学过程中观测到的变形的解释，并有助于选择未来的观测地点。
A number of studies have been carried out in order to determine the magnitude of effects originating from the surroundings of an observation site which influence seismometer records or deformation observations with tilt- or strainmeters. The investigations generally comprise thermal, atmospheric, topographic, and cavity effects, as well as ocean loading. Recently, these studies have been continued and extended using Finite Element (FE) modeling.The effects are investigated exemplarily using air pressure variations as loading signal. The observatory sites differ in their local surroundings. Based on this the influence on topographic and lithologic features is investigated with respect to air pressure changes. The models developed reflect different topographies around stations: wide and narrow valleys, hill flanks, and flat areas. At the foot of the hill flank, galleries are integrated into the models. The topographic and the gallery geometry influence are systematically investigated with regard to e.g. rock coverage above an observation site, changes in the hill slope, width of a valley, and lithology. The deformations are only caused by air pressure changes and not associated with gravity changes due to an advancing pressure front.For loading different air pressure scenarios are simulated with an uniform load and a pressure front which moves over the model in different directions. As an elastic rheology is considered, the effects can be scaled to actual occurring air pressure variations.Initial studies focus on the cavity effect to estimate the order of magnitude to separate the pure cavity effect from other influences. Studies of topographic effects, e.g. an increasing slope angle, yield a non-linear increase in the strain component with amplitudes up to 2 nstrain and tilt changes up to 2 nrad for a uniform air pressure load of 1 hPa for PREM parameterized models. Different lithologies can result in five times larger deformations. For moving high pressure areas, changes emerge in strain of up to 2 nstrain and in tilt of up to 4.2 nrad.The results obtained improve the interpretation of deformations observed with regard to fundamental geodynamic processes, and contribute to the selection of future observation sites.
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DOI：
--
发表时间：
2001
期刊：
影响因子：
--
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T. Jahr;G. Jentzsch;C. Kroner
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--
发表时间：
2006
期刊：
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--
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C. Kroner
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--
发表时间：
1983
期刊：
影响因子：
--
作者：
T. Muller;W. Zürn
通讯作者：
W. Zürn
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
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通讯作者：
H. Steffen
地下水对钻孔倾斜测量的影响
DOI：
--
发表时间：
1991
期刊：
影响因子：
--
作者：
A. Weise
通讯作者：
A. Weise