Ground-Based Measurements of Some Minor Constituents During the Solar Eclipse-1995

1995年日蝕時地面少要素氣體之量測

A. B. Ghosh；S. Bose；M. Lal；A. Maitra

Solar Eclipse ； Aerosol Optical Depth ； Watervapour ； Solar Irradiance

Terrestrial, Atmospheric and Oceanic Sciences

8卷2期（1997 / 06 / 01）

247 - 253

英文

In summer 1995,in collaboration with the deep multi-channel seismicprofiling project around the island of Taiwan,an onshore-offshore wide-angle deep seismic profiling experiment was conducted in Taiwan.The resultsare expected to provide the first complete seismic images of the deepcrustal structure for a better understanding of the Taiwan orogeny andsubduction-collision system.The experiment consists of three profiles,onealong each of the central and southern cross-island highways and anotheron the south-link highway of the island.For the first two lines,35 three-component portable seismographs were deployed along each of the 116 and135 km-long profiles onshore,with airgun shots being fired at distanceseastward form the east coast of up to 133 km and 170 km,respectively.Onthe third line,6 stations were deployed along the 20 km-long profile.Forthis line,the R/V Ewing provided shots from the Philippine Sea westwardto the eastern coast of the Hengchun Peninsula and then from the westerncoast of the Hengchun Peninsula westward away from Taiwan.The totallength of the third line was about 310 km.The average station intervalswere about 4 km.The preliminary results along the three profiles show avery thick crust beneath Taiwan.In addition,the velocity structures showthat lateral variation of velocity in the upper crust is generally larger thanthat in the lower crust and uppermost mantle.Large thickness variationsin the crust were also obtained.The crustal thickness beneath Taiwan diminishesgradually toward the west,but dramatically toward the east.Thetopographic high is not well associated with the crustal thickness.The thickestcrust is to the east of the central mountain range,which may indicatethat Taiwan has not yet reached its isostatic equilibrium.In this paper,thepreliminary results along the southern cross-island profile are given as anexample.Detailed results of the three profiles will be given elsewhere.