Study of characteristics of long-period ground motion response spectra by using broad-band records of the Chinese Digital Seismograph Network

Broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network (CDSN) from 65 earthquakes are used to calculate the horizontal relative displacement, relative velocity and absolute acceleration response spectra with critical damping ratio ζ =0.005, 0.01, 0.02, 0.05 and 0.10, respectively. The results show that it is insufficient to obtain the credible characteristics of long-period ground motion response spectra only with the common ground acceleration records in engineering, while the broad band records of CDSN, as an important supplementary to ground acceleration records, can be used to study the characteristics of long-period ground motion response spectra.

Characteristics of coda Q-value in the midnorthern part of Ningxia

On the basis of previous studies, this paper in studying the coda Q-valuc of near shocks, has proposed using the sampling depth to describe the effect of lapse time on the Q-value, and has investigated the dependence of coda wave of earthquakes on frequency and sampling depth. Analysis of digital seismograms recorded by the Yinchuan Telemetric Seismic Network, Ningxia, shows that not only the coda wave Q-value of shocks is strongly dependent on frequency but also its dependence on Samling depth cannot be neglected. In the commonly used formula that describes the dependence cbaracteristics of coda Q-value of endquakes, Q = Qof', the parameter Qo rises obviously whilc n drops when the sampling depth increases, and their changes can be fitted by linear relations. This paper has explained such a characteristic. Whether this characteristic exists universally needs to be verified by more study results because the genetic mechanism of coda wave of earthquakes is more complex.

Study on the method for comprehensive discrimination of small earthquakes

In the paper, we apply the theory of modern digital signal processing to analysis 3-component digital seismic data recorded in Datong area of Shanxi Province by digital seismographs developed by the Institute of Geophysics, CSB in November 1999 and study the auto-discrimination of the recorded digital seismic signals. The result shows that the method for comprehensive discrimination in connection with ratios between average values of long-time and shorttime signals, spectral analysis, and wavelet analysis can be used to auto-discrimination of seismic signals through alternate man-computer processing. Many ML>2.0 earthquakes were discriminated better.

Catalogs of ground motion parameters for earthquake-prone regions in Kazakhstan

The catalogs of ground motion parameters for earthquake-prone regions of Kazakhstan used for modeling seismic effects in seismic hazard assessment and microzonation are presented.

Study on the Source Parameters of the Barkam Earthquake Sequence

Using digital wave data recorded by the Barkam station, source parameters for 93 earthquakes with ML2.5 - 5.0 in the Barkam area are determined by spectral analysis. PreHmiuary analysis of the source parameters show that there is a high correlation between seismic moment Mo and local scale ML, which is lgtoMo = 0.92ML ＋ 10.24,correlation coefficient R is 0.86; Investigation of the relationship between stress drop and local scale ML indicates that the stress drop seems to be independent of ML.

Analysis on the Characteristics of the Coseismic Response of Water Levels Recorded in Three Wells in Hainan,China to the Two Sumatra-Andaman Strong Earthquakes

The characteristics of seismic water level fluctuations of the two Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 on December 26,2004 and March 29,2005 recorded at Jiaji well,Qionghai,Hainan were analyzed,the features of the infrequent "step" changes of well water level after the two earthquakes were also analyzed and the mechanism of the "step change" of well water level was discussed.Then the high-sample-rate digital observation data of seismically-induced water level fluctuations of the Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 recorded at Nanbin well,Sanya and Tanniu well,Wenchang were analyzed.The results suggest that the dominant period of the seismic well water level fluctuation in all three wells was comparatively accordant,the amplitudes of seismic water level fluctuation of the same earthquake in different wells were clearly different,the time duration of seismic water level fluctuations of different earthquakes at the same well was also clearly different.

Review on theory and applications of wavefront recording plane framework in generation and processing of digital holograms

The wavefront recording plane （WRP）, subsequently generalized to be known as the virtual diffraction plane （VDP）, is a recent concept that has been successfully deployed in fast generation and processing of digital holograms. In brief, the WRP and its extension, the VDP, is a hypothetical plane that is located between the hologram and the object scene, and which is at close proximity to the latter. As such, the fringe patterns on the hypothetical plane are carrying the holistic information of the hologram, as well as the local optical properties of the object scene. This important property enables a hologram to be processed with classical image processing techniques that are normally unsuitable for handling holographic information. In this paper we shall review a number of works, that have been developed based on the framework of the WRP and the VDP.

Prejudgments for Reference Potential Determination to Quantitative EEG Interpretation:Amplitude Distribution and Ear-lobe Activation

This paper presents an automatic techruque of suitable reference potential selection for quantitative EEG interpretation.The 16-channels EEG recording under mono-polar derivation is analyzed.There are two prejudgments defined for checking the amplitude distribution and ear lobe activation.After prejudgments,the EEG is classified into several cases in cluding diffused case,non-diffused case,and artifact contami nation case.Due to the cases,an automatic reference selection method is applied in order to find out suitable reference potential.Finally,the referential derivation constructed according to the obtained reference potential,is evaluated for further EEG rhythm analysis.The presented technique can high light the EEG rhythm of interest,which is useful for quantitative EEG interpretation by both visual inspection and automatic evaluation.