Current measurements made in the Taiwan Strait from March to July 1984, confirmed old ship reports that flow was toward the north in both summer and winter. The flow consists of three parts: a steady current which is about 27 cm sec–1 in both seasons, a long-period (period longer than 20 days) fluctuating component which varies with the reverse of wind direction between seasons (monsoon wind), and a short-period (period in the range of 3 to 20 days) fluctuating component which is closely related to the frontal passages and appears only in winter. Thus, a permanent source must exist at the southern end of the strait that drives the steady flow to the north regardless of season. The northward mean flow is then modulated by the seasonal wind field, and hence, shows different characteristics between seasons. 相似文献
Our field investigation obtains new evidence of the later Quaternary activity and recent large earthquake ruptures of the Garzê-Yushu fault. The average left-lateral slip-rate along the fault is determined to be (12±2) mm/a for the last 50000 years from both offset landforms and ages of the correlative sediments. This result is very close to the estimated average left-lateral slip-rate for the Xianshuihe fault, suggesting that the horizontal movement along the northern boundary of the Sichuan-Yunnan active tectonic block and the northeastern boundary of the Qiangtang active tectonic block has been basically harmonious during the later Quaternary period. Remains of ground ruptures of recent large earthquakes have been discovered along all 3 segments of the fault, of which, the 1896 rupture on the northwestern segment is at least 70 km long, and its corresponding earthquake could be of moment magnitude 7.3. The latest rupture on the middle segment of the fault has a length of about 180 km, and was produced by an unknown-age large earthquake that could have a moment magnitude of about 7.7. Along the southeastern segment of the fault, the latest unknown-age rupture is about 65 km long and has a maximum left-lateral coseismic displacement of 5.3 m, and its corresponding earthquake is estimated to be as large as about 7.3 of moment magnitude. Based on relevant investigation, an inference has been drawn that the later two large earthquakes probably occurred in 1854 and 1866, respectively. These demonstrate that the individual segments of the studied Garzê-Yushu fault are all able to produce large earthquakes.
We are involved in an embarrassing situation that the limited capa-bility of automated feature extraction in digital photogrammetric systems cannotsatisfy the increasing needs for rapid acquisition of semantic information for appli-cations.Facing this challenge,a new tactic,Human-Computer Collaborative(HCC)tactic,and a corresponding new method,Operator-Object Directed(OOD)method,are proposed for the design of a system for feature extractionfrom large scale aerial images.We hold that in almost all technical complex sys-tems,full automation will be neither technically feasible nor socially acceptable.The system should be designed to optimize through the cooperative operation withtwo agents in the system:the human and the computer. 相似文献
In this paper,multiquadric equations interpolation is used to establish a widely covered and valuable speed field model,with which the crustal movement image is obtained. 相似文献