云南天文台高分辨率斑点成像的新进展

本文报道了对天文目标：双星ＡＤＳ１６８００、ＡＤＳ１６１７３,三星Ｈｕ６６（ＡＤＳ１１３４４）和Ｈｌｄ１７１（ＡＤＳ１６６４８）进行的斑点成像观测及测量结果。介绍了所用的二维光子计数斑点像探测系统的性能,分析了探测系统的光子噪声、附加噪声和其它更复杂的噪声对斑点图的平均功率谱和重谱的影响。在讨论了改正重谱中的噪声偏差项时提出了对重谱基底施加正性约束的算法。测量的结果表明,实现了高精度的微射受限天文     

Input parameters for estimating seismic loading

The estimation of seismic loading requires both the featuring of the seismotectonic environment as well as a prognosis of site-specific strong ground-motion parameters. Due to the long recurrence times of larger events, there is a lack of high quality strong motion recordings at many sites. The use of seismograms obtained from different seismotectonic regions, additionally recorded under different subsoil conditions, poses several questions as to the significance of the assessment of seismic loading. A way to overcome these problems is the generation of synthetic seismograms, e.g. by the use of Boore's stochastic procedure. Subsoil conditions may be explicitly included in the simulation as proposed by Kunze et al. In this context, the seismotectonic environment forms the deterministic frame of any stochastic strong ground-motion simulation. In terms of Boore's approach, seismic moment, global stress drop, high frequency cut off, and focal depth act as controlling parameters. In order to achieve a more realistic assessment of possible seismic loading, a classification of seismoactive zones should account for parameter vectors as described above rather than for single parameters like magnitudes or intensities. A tool to attack this task may be found in cluster analysis, which is a type of pattern recognition based on statistical considerations. Crucial to this technique, however, is the use of properly estimated parameters, which still cause discussion in the seismological community. Problems and chances of the approach are discussed with examples from the Swabian Jura and the Rhine graben.Paper presented at the 21st General Assembly of the European Seismological Commission held in Sofia, 1988.     

Plastic-Flow Waves ("Slow-Waves") and Seismic Activity in Central-Eastern Asia

The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, “fast-waves" and “slow-waves", are induced in the lower lithosphere (including the lower crust and lithospheric mantle) under driving at plate boundaries and both of them are viscous gravity waves formed by the superposition of major and subsidiary waves. The major waves are similar to solitary waves and the subsidiary waves are traveling waves. The plastic-flow waves in the lower lithosphere control seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wave-crest belts. “Fast-waves" propagated with velocities of orders of magnitude of 100～102km/a have been verified by wave-controlled earthquake migration, showing the “decade waves" and “century waves" with the average periods of 10.8 and 93.4 a, respectively, which originate from the Himalayan driving boundary. According to the recognition of the patterns of the belt-like distribution of strong earthquakes with M S≥7.0, it is indicated further in this paper that the “slow-waves" with velocities of orders of magnitude of 100～101 m/a also originated under compression from the Himalayan driving boundary. Strong earthquakes with M S≥7.0 are controlled mainly by subsidiary waves, because the major waves with a duration of up to 106 a for each disturbance cannot result in the accumulation of enough energy for strong earthquakes due to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445 km, velocities of 0.81～2.80 m/a and periods of 0.16～0.55 Ma. The wave-generating time at the Himalayan driving boundary is about 1.34～4.59 Ma before present for the “slow-waves", corresponding to the stage from the Mid Pliocene to the Mid Early-Pleistocene and being identical with one of the major tectonic episodes of the Himalayan tectonic movement. It is shown from the recognition of the wave-controlled belts of strong earthquakes that two optimal patterns of wave-crest belts originated simultaneously from the eastern and western segments of the Himalayan arc, respectively. The overlap of wave-crest belts of these two systems is responsible for the relative concentration of energy and forms the seismic-energy-background zones for strong earthquakes with M S≥7.0.     

强地震引起的同震形变响应

以华北地区地倾斜、地应变数字化观测为基础,研究了形变同震响应的分布特征,给出了地震面波响应延迟时间、响应幅度、同震信号持续时间(在可分辨的范围内)等特征与地震震中距离及震级之间的关系,同时还探讨了短临形变前兆与未来地震之间可能存在的关系及地震短临预测面临的科学问题。     

台湾海峡强震活动及其动力环境

本文根据１９９４年９月１６日台湾海峡７．３级强震序列的空间活动图象变化特征，结合历史地震资料，比较分析了台湾海峡区域史今地震活动的总体演变过程，表明该区强震发生与周边地区的台湾，日本及菲律宾大地地震，在时间进程，强度变化和地域分布关系上存在关地球物理场变化的影响。     

侧扫声纳系统成图中的位移、变形和噪声问题

侧扫声纳声图判读的正确性和准确性对海洋工程的实施和维护中具有非常重要的作用。但诸多影响因素的存在使得声纳声图不能真实反映海底状况。了解这些因素，并在判读过程中尽可能消除其影响，以达到正确和准确判读是非常有意义的。本文将这些影响因素按照作用结果分为位移、变形和噪声3个大类，并对其校正或消除方法进行讨论。     

有ARMA噪声的一种参数估计的优效性

对于有ARMA噪声的线性回归模型,本文给出了只用递推进行模型辨识和参数估计的线性方法。若用所计算得到的回归残差作为数据,采用Hannan-Rissanen的线性估计法求ARMA噪声的参数估计,则本文证明了估计是强相容的,且对正态序列,估计具有渐近正态优效性。     

Variation of underwater ambient noise observed at IORS station as a pilot study

The Ieodo Ocean Research Station(IORS) is an integrated meteorological and oceanographic observation base which was constructed on the Ieodo underwater rock located at a distance of about 150 km to the south-west of the Mara-do, the southernmost island in Korea. The underwater ambient noise level observed at the IORS was similar to the results of the shallow water surrounding the Korean Peninsula (Choi et al. 2003) and was higher than that of deep ocean (Wenz 1962). The wind dependence of ambient noise was dominant at frequencies of a few kHz. The surface current dependence of ambient noise showed good correlation with the ambient noise in the frequency of 10 kHz. Especially, the shrimp sound was estimated through investigations of waveform and spectrum and its main acoustic energy was about 40 dB larger than ambient noise level at 5 kHz.