The S wave velocity structure of the earth below Eastern Southeast Asia has been investigated by analyzing the seismogram from surface wave to multiple depth waves in the time domain and three Cartesian components simultaneously. The wave passes across the front area of subduction zone between the Philippine plate and the Asian plate. The main data are waveform comparisons, instead of the arrival times. The synthetic seismogram is calculated using the GEMINI method. The synthetic seismogram constructed by PREMAN global earth model deviates greatly from the measured one. To solve this problem, corrections are needed for the β speed structure. Corrections cover the gradient change of βh, which turns from negative to positive in upper mantle layers as in the PREMAN, change of earth crust depth and change of zero order coefficients of β velocity function in all earth mantle layers. So, the fitting is obtained, as well as the arrival time or the waveform of Love and Rayleigh surface waves, the S wave and the repetitive depth waves ScS2 and ScS3. This result reveals that the Southeast Asia, being stretched due to tectonic release, has a mantle in some parts with negative anomaly of S wave velocity and vertical anisotropy in all earth mantle layers. 相似文献
We present a mathematical model of local, steady groundwater flow near a vertical barrier wall. Flow features represented in the model include an impermeable arc-shaped barrier wall and multiple wells; distant boundary conditions are not included explicitly, but their effects on the local flow field are modelled by specifying a uniform flow at infinity and a constant areal recharge within a local domain. We develop an explicit closed-form solution to the boundary-value problem using the analytic element method. The solution is an extension of a harmonic solution presented by Anderson and Mesa [Anderson EI, Mesa E. The effects of vertical barrier walls on the hydraulic control of contaminated groundwater. Adv Water Resourc 2006;29(1):89–98] which does not include the effects of recharge. We demonstrate that the general solution with recharge consists of the harmonic solution superposed on a special case of the harmonic solution along with two elementary one-dimensional flow solutions. The results are used to investigate the effects of areal recharge on the capture zone envelopes of the pumping wells and on the reduction in discharge that can be achieved by including a barrier wall in a pump and treat design. We find that the benefits of including an open barrier wall in a design, measured as a reduction in the pumping rate required to contain a plume, increase for higher recharge rates. Dimensionless plots of capture zone envelopes are presented for a practical well and barrier wall configuration. 相似文献