A Regional GPS Network Solution for Monitoring Deformations of the Southeastern Eurasian Plata

GPS Solutions - Investigations of deformation styles in Asia have already led to new kinematic models that predict the spatial and temporal evolution of deformations in the region. Testing these...     

Ore mineralization in volcanic rocks from the submarine rises of the Sea of Japan

The electron microprobe investigation of volcanic rocks from the submarine rises of the Sea of Japan revealed for the first time numerous inclusions of small grains containing metals (Cu, Zn, Sn, Ni, Pb, As, Cr, W, Ti, Ta, Fe, and Ag), mainly as native elements, intermetallic compounds, phosphides, oxides, sulfides, and sulfates. These grains are usually confined to the walls of microscopic fractures and pores or fill microscopic cavities and interstices in the groundmass and in rock-forming minerals. Taking into account that native metals, intermetallic compounds, and phosphides are indicative of a high-temperature gaseous fluid, it can be supposed that such a fluid was the source of metals.     

An efficient technique for creating a continuum of equal-area map projections

Equivalence (the equal-area property of a map projection) is important to some categories of maps. However, unlike for conformal projections, completely general techniques have not been developed for creating new, computationally reasonable equal-area projections. The literature describes many specific equal-area projections and a few equal-area projections that are more or less configurable, but flexibility is still sparse. This work develops a tractable technique for generating a continuum of equal-area projections between two chosen equal-area projections. The technique gives map projection designers unlimited choice in tailoring the projection to the need. The technique is particularly suited to maps that dynamically adapt optimally to changing scale and region of interest, such as required for online maps.     

How do Unmodeled Systematic Mean Sea Level Variations Affect Long-term Sea Level Trend Estimates from Tide Gauge Data?

Although there are over 1,800 globally distributed tide gauge stations, only a few hundred of them are suitable for monitoring and analyzing global mean sea level (MSL) changes. This is because several tide gauge records span short periods of time and therefore their trend estimates are adversely affected by unmodeled systematic sea level changes such as seasonal, interannual, decadal variations. This limitation can be improved by using more elaborate models that account for systematic fluctuations in MSL for shorter time-series. In this study, analytic expressions were derived to analyze and quantify the epoch-by-epoch and lump-sum effects of these systematic changes to the local MSL trend estimates as a function of the time-series‘ lengths. The numerical results reveal that systematic MSL variations, particularly transient/episodic ones, if they are not properly modeled or omitted from the models, will bias the trend estimates for the tide gauge data series around the world by up to 0.6 mm/year for the 50-year time-series that are needed for more reliable inferences about global MSL. Random effects, which are not a factor in estimating MSL trends for the long-term (>50 years) time-series, need to be scrutinized together with the systematic errors for time-series shorter than 50 years.     

A preliminary error analysis of the gravity field recovery from a lunar Satellite-to-Satellite mission

Summary A low cost lunar Satellite-to-Satellite radio tracking mission in a low-low configuration could considerably improve the existing knowledge about the lunar gravity field. The impact of various mission parameters that may contribute to the recovery of the gravity field, such as satellite altitude, satellite separation, mission duration, measurement precision and sampling interval were quantified using the Jekeli-Rapp algorithm. Preliminary results indicate that the gravity field resolution up to harmonic degree 40 to 80 is feasible depending on various mission configurations. Radio tracking data from a six-month mission with a precision of 1 mm s^–1 every 10 s and 300 km satellite separation at 150 km altitude will permit the determination of 5^o×5^o mean gravity anomalies with an error of approximately 15 mgals. Consideration of other unaccounted error sources of instrumental, operational as well as environmental nature may lower this resolution.     

地基GPS技术遥感香港地区大气水汽含量

提出了分段多项式方法计算大气水汽含量,并结合无线电高空气象探测资料,分析并评估了地基ＧＰＳ遥感技术的精度。香港地区的可降水份计算结果表明,地基ＧＰＳ遥感技术的精度为１ ｍ ｍ ～２ ｍ ｍ     

Response of a 2-story test-bed structure for the seismic evaluation of nonstructural systems

A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismic performance of nonstructural systems including steel-framed gypsum partition walls, suspended ceilings and fire sprinkler systems. The frame can be configured to perform as an elastic or inelastic system to generate large floor accelerations or large inter story drift, respectively. In this study, the dynamic performance of the linear and nonlinear test-beds was comprehensively studied. The seismic performance of nonstructural systems installed in the linear and nonlinear test-beds were assessed during extreme excitations. In addition, the dynamic interactions of the test-bed and installed nonstructural systems are investigated.