Estimating the Areas of High-Frequency Wave Radiation on the Fault Plane of the 2008 Mw 7.9 Wenchuan, China, Earthquake by Envelope Inversion

ABSTRACT We estimated the areas exhibiting high-frequency (1∼10 Hz) wave radiation on the fault plane of the 2008 Wenchuan earthquake, by applying envelope inversion to strong-motion acceleration records. The corrected records of two small earthquakes are adopted as the empirical Green’s functions. Considering the change in the rupture pattern of the Wenchuan earthquake from southwest to northeast, the records of small earthquakes dominated by thrust and strike-slip are utilized as the empirical Green’s function for the southwestern and northeastern fault sections, respectively. The results are as follows: (1) According to the high-frequency wave radiation, the rupture process is complex. High-frequency waves radiated strongly in six areas: around the initial rupture point, along the north and south edges of the fault plane, near the area of intersection with the cross-cutting Xiaoyudong fault, south of Nanba, and near the area of Qingchuan. In total, these areas can be divided into three cases. In the first situation, high-frequency waves radiated strongly around the initial rupture area, which may be associated with the initiation of rupture and a high stress drop. The second location is near the periphery of the fault, which is associated with the termination of rupture. The third condition comprises high-frequency waves near the intersection with the cross-cutting Xiaoyudong fault. This area as a geometric barrier, and the surface rupture is observed. (2) The distribution patterns of the high- and low-frequency radiation intensity differ on the fault plane. From the hypocenter to the point of intersection with the Xiaoyudong fault, the high-frequency wave is located around the area with large slip value. In other areas, the distribution of the high- and low-frequency radiation is no obvious relationship. This different characteristic indicates the complexity of the rupture process.

Stealth Detection System via Multistage Radar and Quantum Radar

In today’s era of advanced weapons and technology development, many remarkable inventions have shifted the balance of war towards the strategically enhanced military equipped with tactical weapons and armaments. One of these strategic advancements is stealth technology due to which stealth aircraft are high in demand for the military. The question that rises is How to detect a stealth object? This paper proposes a novel anti-stealth technique using void detection, high frequency wave interference and neutrino beam propagation. Void detection method uses a modified satellite-based radar that searches for areas in the aerospace from which the transmitted signals sent to the ground receiving station are blocked or deflected. High frequency wave interference method is used to generate a stellar trajectory of the stealth aircraft at the detected void. Neutrino beam comprises of energy quanta mainly neutrinos, which are able to surpass the absorption or deflection systems in the stealth body of aircraft. This unique phenomenon produces a moving image, which is the precise location of the aircraft in the space. Using these methods, the trajectory of the aircraft is detected which ultimately leads to the detection of the stealth aircraft itself. The newly proposed methods which are theoretically more reliable than the existing methods may not have been tested but the method planning make them practically feasible considering that the technology used is a part of advanced engineering today.

Thin-layer solutions of the Helmholtz equation

This paper gives a brief overview of some configurations in which high-frequency wave propagation modelled by Helmholtz equation gives rise to solutions that vary rapidly across thin layers. The configurations are grouped according to their mathematical structure and tractability and one of them concerns a famous open problem of mathematical physics.