Comparative study on the deviation characteristics of post-earthquake intensity evaluation based on two intensity attenuation relationship models

We collect the isoseismal data of 488 earthquakes in western China and 182 earthquakes in eastern China after 1900.The least square method is used to establish two models of the seismic intensity attenuation relationship partitions in China,based on the major and minor axis ellipse models,and the area and the major axis radius,respectively.The two models are applied to the calculation of the intensity circle of the earthquake events with a magnitude M_(S)≥5.0 from 2008 to 2019,and the actual intensity is compared with the model intensity value as an indicator to verify the consistency between the actual intensity and the value from the empirical statistical model.Three real earthquake results are selected to calculate the major and minor axis and area of the ellipse using the two intensity attenuation relationship models.After comparison,we summarize the deviation characteristics of the intensity value,and put forward corresponding improvement suggestions.

Parameter Fitting of Seismic Intensity Attenuation Model in Xinjiang

By using the existing historical earthquake investigation data in Xinjiang,this paper obtained the envelope curves of isoseismal maps of 103 destructive earthquakes occurring from 1716 to 2010 after digitization of the data. The author summarized the seismic intensity attenuation laws in the Xinjiang region with the multiple regression fitting method. The intensity attenuation function of the elliptical model was provided and the fitting results in different periods and areas were compared. Finally, the intensity attenuation relationship in the Xinjiang region was obtained by the method of constraining the start and end of the attenuation curves.

Macroseismic intensity attenuation in Iran

Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismic intensity attenuation based on 560 intensity data obtained in Iran in the time period 1975-2013. The geometric spreading and energy absorption of seismic waves have been considered in the proposed model. The proposed easy to implement relation describes the intensity simply as a function of moment magnitude, source to site distance and focal depth. The prediction capability of the proposed model is assessed by means of residuals analysis. Prediction results have been compared with those of other intensity prediction models for Italy, Turkey, Iran and central Asia. The results indicate the higher attenuation rate for the study area in distances less than 70 km.

Study of the intensity attenuation law in the East China Plain and the northwest of China

In order to obtain the intensity attenuation law in the north of China, the studied region is divided into four regions according to topographical and geological feature.For making the shape of isoseismal lines from ellipse to circle with the increase of distance,the tail-limited method is derived.Using the ellipse-projection,two-step regression,head-limited and tail-limited method,their intensity attenuation laws are obtained.Through the study of the intensity attenuation law in the greater part of China,the author considers that the intensity attenuation law of China can be roughly divided into:plain-type and mountain-type.So the intensity attenuation law in East China Plain(plain-type for short) can be used in plains and deposit areas and that of the greater part of the regions in Yunnan and Sichuan Provinces(mountain-type for short) can be used in mountains.For the earthquakes occurred on the borders,their attenuation laws are classified respectively.In the side of mountains belong to mountain-type,and in the side of plain plain-type.In the areas where two kinds of topograph intersect isoseismal lines are irregular and the attenuation laws are more complex.

Properties of sound attenuation around a two-dimensional underwater vehicle with a large cavitation number

Due to the high speed of underwater vehicles, cavitation is generated inevitably along with the sound attenuation when the sound signal traverses through the cavity region around the underwater vehicle. The linear wave propagation is studied to obtain the influence of bubbly liquid on the acoustic wave propagation in the cavity region. The sound attenuation coefficient and the sound speed formula of the bubbly liquid are presented. Based on the sound attenuation coefficients with various vapor volume fractions, the attenuation of sound intensity is calculated under large cavitation number conditions. The result shows that the sound intensity attenuation is fairly small in a certain condition. Consequently, the intensity attenuation can be neglected in engineering.

Complex of general seismic zoning maps OSR-2017 of Uzbekistan

The quantitative assessment of seismic hazard of Uzbekistan has been examined,and new maps of seismic zoning has been developed.Quasihomogeneous seismological areas and seism-generating zones are considered as seismic sources,based on the analysis of seismotectonic data.The seismological parametrization of seismic sources has been carried out,including determination of parameters of earthquake’s reoccurrence for different power levels,seismic potential and a predominant type motion in the source of occurring earthquakes.The reoccurrence parameters of seismic sources were both determined by directly from Gutenberg-Richter dependence law and using summation and distribution methods.Setting were conducted separately for a sample of strong(M≥5)and weak(M<5)earthquakes.The seismic potential Mmax of seismic active zones was determined by seismological and seismotectonic methods.The predominant type of movement in the faulting for each seismic source is reverse fault.Regional regularities of seismic intensity attenuation with distance of different power levels are determined.The seismic hazard is expressed in points of a macro seismic scale,in velocities and accelerations of ground motions,and it is characterized by calculated seismic intensity with the set probability(P=0.9,P=0.95,P=0.98 and P=0.99)not exceed within 50 years in the constructed maps.In seismic zoning map,the seismic intensity was in average soil conditions.The developed complex of maps considers a number of uncertainties of the input parameters in relation to both incompleteness of initial seismological and seismotectonic data,as well the probabilistic nature of seismic process and seismic intensity.The factors of uncertainty of the input parameters are taken into account by constructing a logic tree.The constructed maps of the general seismic zoning are intended for imple menting antiseismic actions in Uzbekistan.

Random pinhole attenuator for high-power laser beams

The intensity attenuation of a high-power laser is a frequent task in the measurements of optical science.Laser intensity can be attenuated by inserting an optical element,such as a partial reflector,polarizer or absorption filter.These devices are,however,not always easily applicable,especially in the case of ultra-high-power lasers,because they can alter the characteristics of a laser beam or become easily damaged.In this study,we demonstrated that the intensity of a laser beam could be effectively attenuated using a random pinhole attenuator(RPA),a device with randomly distributed pinholes,without changing the beam properties.With this device,a multi-PW laser beam was successfully attenuated and the focused beam profile was measured without any alterations of its characteristics.In addition,it was confirmed that the temporal profile of a laser pulse,including the spectral phase,was preserved.Consequently,the RPA possesses significant potential for a wide range of applications.