Analysis Of The Energy Radiation Sources Of The 2004 Sumatra-Andaman Earthquake Using Time-Domain Array Techniques

Firstly, theoretical background of two seismic array techniques on a basis of the raytheory, the Beam Power Analysis and the Migration Stacking, are introduced. Theformer is suitable for plane waves, and the later is suitable for both plane waves andspherical waves.Two arrays are formed with stations of the Capital Region Digital SeismographNetwork (CRDSN) of Beijing for this study. One is equipped with short-periodseismometers, and another is equipped with broad-band seismometers. Different arrayhas different array transfer function (ATF), and different array has different array gain.The ATF and array gains of the above two arrays are discussed. Also the skills ofsetting parameters in determination of the apparent slowness vector are simplyillustrated.The software is made using Matlab computer language as a tool of processing arraydata in time domain for determination of the radiation sources of large earthquakesbased on the principle presented in the previous chapter, so a brief introduction of themain functions and structures of the software is made. The reliability of the softwareis tested as well as the effects of the geometry of arrays on the locating results bymeans of some numerical tests.The 2004 Sumatra-Andaman huge earthquake was followed by a number ofmoderate-magnitude aftershocks. It allows us to correct the radiation sources of themain-shock using the aftershocks' locations under condition of assuming the locationsof these aftershocks published by NEIC were correct. It is discussed that how thelocations of the radiation sources of the main-shock are corrected and two approachesof correcting locations, named Interpolation Correction and Fitting Correction,respectively, are proposed for different situations.Finally, the two techniques are applied to the short-period recordings and broadbandrecordings of CRDSN generated by the 2004 Sumatra-Andaman huge earthquake forthe locations of the energy radiation sources, and the source information regarding ofrupture duration, tempo-spatial process, fault geometry, average rupture velocity andothers is obtained.