Search

Heterodyne laser interferometer, which is used as a sensor for high-precision displacement measurement, is used to measure the ground motion and seismic waves as a seismometer. Through the displacement variation obtained by the precision measurement, we predict the magnitude of the earthquake. The Recursive Least Square (RLS) method reduces the error of earthquake magnitude prediction. RLS method is to update the relation between the magnitude and P d adaptively to predict the magnitude of earthquake more accurately. With the simulation results, we reduced error factors and improved the accuracy of earthquake magnitude estimation.

Wave is a general term given to ‘disturbance in water’. The waves produce humungous amounts of energy and therefore the study of different characteristics associated with waves becomes an important aspect. One such characteristic is the wave height. The height of a wave determines the impact that it would have when it hits the surface thereby playing a crucial role in deciding the quality and commercial viability of a beach and in determining the extent of transportation of sediments to proximate coastal areas. If the wave becomes very vigorous then it would pose a serious threat to the lives of the people inhabiting coastal areas. Therefore the analysis of different characteristics of waves becomes all the more important. In this paper, we have presented a statistical estimation of one such characteristic namely the wave height, which is also one of the most significant parameters used for estimating wave energy. In our review, we have used fundamental distribution functions to model the wave height, and have calculated error using various error detection tests thereby concluding the best fit for wave height. We have also provided a retrospective view of wave energy potential, in the light of significant wave height analyzed.

The statistical analysis of short wave data about B1 and B2 wave measure station around Toumen Island in Taizhou sea area showed that: the normal and strong wave direction are between east to southeast, the big wave is mainly impact by typhoon, annual average significant wave height is less than 0.7 m, and the frequency of annual average wave period great than 7s is 0.6%, matching the wave spectral by standard spectral, the relative wave parameter P is 1.53 for B1 station, and 1.75 for B2 station.

The estimation of oceanic crust structure is required to reveal the development history of Japanese island arcs and to estimate the limit of legal continental shelf. Refraction or reflection wave exploration is one of the methods for deep oceanic crust investigation, but these methods use only compressional wave or the depth component of a seismometer. Hence, it is needed to use shear wave or horizontal component of seismograms for more precise investigation to estimate the thickness of the oceanic crust. Receiver function is a function to estimate the interface of velocity change using shear wave from an earthquake without artificial sources. This study tries to apply receiver function analysis to the investigation using refraction wave not from an earthquake but artificial sources on the ground or sea surface. After the transformation of depth-horizontal coordinates into radial-tangential coordinates, the Ps converted wave can be observed clearly. We confirm the effect of the receiver function analysis as one of the methods of estimating velocity boundaries and its application to refraction seismic survey.