地球物理学前沿

1、C1:背景噪声成像主要流程？a）下载数据（2-3年的连续波形数据）。b）连续数据离散化。c）预处理。d）地震数据去除，而后补齐（正变为1，负变为-1）。e）台站队互相关。f）叠加。g）提取Vp，Vg（相速度和群速度）。h）反演地下三维结构。A）download data （2-3 years of continuous waveform data）.B）discretization of continuous data.C）pretreatment.D）seismic data are removed, and then filled （positive to 1, negative to -

2、1）.E）interstaion cross-correlation. obtainGreen function from two stations.F）stacking.， obtaina more reliable Green function.G）extractVp and Vg （phase velocity and group velocity）.H）Inversion of underground 3D structure.蒙特洛反演的大致流程？流程：a）输入观测数据和必要的判别指数；b）在一定的原则下,有指导的随机的生成模型；c）对初始模型进行正演计算,并检验它是否合符要求。保留

3、合格解，撇弃不合格解；d）如是不合格解，则返回b），如合格，则终止程序。优点：a）适应性很强，受条件限制小,不管有多复杂的问题,不管其维数多高，非线性程度多 大,都可以使用。而且可以获得满意的解或解集b）由于蒙特卡洛法的收敛速度与问题的维数无关，因此特别适用于大规模、多参数问题的 反演c）蒙特卡洛法易于编程,占用内存不大d）便于理解缺点：a）收敛速度不可能快，这就大大地增加了计算时间和成本,使它在实际应用中受到了很 大的限制b）蒙特卡洛法的误差仅具有概率性质,其解是在某一置信度或概率意义下求得的最佳 解,不具通常意义下的最佳性质process：A）input observational dat

4、a and necessary discriminant indices;b）guided random generative model under certain principles；c）forwardmodeling of the initial model and test whether it is true or not Coincidence requirement. Retain qualified, unqualified cast solution;D) if it is unqualified, then return to B, if qualified, then

5、terminate Program. Advantage：(a) adaptability is very strong, the condition is limited, no matter how complex the problem, regardless of its dimension is high, the degree of nonlinearity, can be used. Moreover, satisfactory solutions or sets of solutions can be obtainedbecause the convergence speed

6、of the Monte Carlo method is independent of the dimension of the problem, it is especially suitable for the inversion of large scale and multi parameter problemsC) Monte Carlo method is easy to program and occupies little memoryD) easy to understandShortcoming:The convergence speed of a can not be f

7、ast, which greatly increases the computing time and cost, so that it is greatly restricted in practical applicationsThe error of Monte Carlo method is only probabilistic, and its solution is the best solution which is obtained in a certain confidence or probability sense, and does not have the optim

8、al resolution usually.C4:接收函数的计算方法？答：a)选择30到90的数据。b)做预处理。进行反褶积。select data thatEpicentral distancesfrom 30 degrees to 90 degrees.preprocessing.Deconvolution .为什么单纯界面深度所得结果没有采用厚度所得结果准确？答：利用克拉贝隆曲线，由界面深度可反推温度变化。由于存在系统误差，用其差值来反推 温度变化更加精确。Using the Clapeyron curve, the interface depth of backstepping tem

9、perature change. Because of the system error, it is more accurate to deduce the temperature change with the difference.P61图3频带变宽原因？有几种矿物的变化，其多样性引起了间断面变化。含水，含水量不同，不同位置相变不同。板块堆积，两侧温度变化较大。温度变化。(a) there are several mineral changes, and their diversity leads to discontinuity variation.B) water content i

10、s different, different positions of phase change.(c) stagnant slab, the temperature change on both sides is large.temperature change.C5:震源深度定位方法？a）单台法b）多台法（交切法和虚波速度法）A）single station methodB）multi station method （intersection method andVirtual wave velocity method）C6：为什么转化波s波比p波弱（进入海底前）？（由斯涅尔定律计算可得。

11、）It can be calculated by Snells principal.海洋地震定位难度？a）震源附近密度小，衰减强。b）台站少。c）背景噪声强。d）洋中脊附近震源深度浅，传统方法不可行。A）The density near the a source is small and the attenuation is strong.B）fewer stations.C）strongambient noise.D）the focal depth near the mid ocean ridge is shallow, and the traditional method is infeasible.海洋多次波的特点？a）振幅衰减b）极性变化a）Decreasing Amplitude.b）Reversed PolarityC7:近震数据可得到什么？存在什么问题？分辨率如何？成像范围怎样？远震数据可得到什么？存在什么问题？分辨率如何？成像范围怎样？联合反演可解决什么问题？近震数据反映浅部构造，纵向分辨率随深度衰减强LocalEarthquakedata reflect the shallow tectonic， with depthincreasingvertical resolution attenuatequickly