in the form of passive seismic methods, broadband seismometers have been used in hydrocarbon exploration. the frequency bandwidth typically studied is in the range of 1–6 hz. the observations on low frequency band of microtremors are used to calculate the spectral ratio of vertical and horizontal components (v/h) and power spectral density (psd). attributes based on the v/h ratio and the psd ha...

It is hypothesized that interplay of earthquake, soil, foundation and structure (SFS) dynamic characteristic, and their interaction in time domain, control the behavior of SFS system during earthquakes. Moreover, (passive and active) control of spatial and temporal location of seismic energy dissipation (preferably in soil) can improve safety and economy of SFS systems. Such energy dissipation ...

We demonstrate with synthetic seismic data the superresolution and super-stacking properties of time reversal mirrors (TRM). Tests on synthetic data show that TRM has the potential of exceeding the Rayleigh resolution limit by a factor of more than 9. This property is accompanied by the fact that TRM has a significant resilience to strong noise. Computer tests validate these properties by accur...

Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical obs...

In this paper we analyze the signals from passive infrared (PIR) and seismic sensors to detect people. The PIR data analysis is done to determine the radiation source such as a human or an animal based on the signal strength, slopes of the signals, the number of Fresnel lens zones crossed by the target. The seismic data analysis is done to ascertain whether the footsteps belong to a human or an...

An analysis of a passive seismic method for subsurface imaging is presented, in which ambient seismic noise is employed as the source of illumination of underground scatterers. The imaging algorithm can incorporate new data into the image in a recursive fashion, which causes image background noise to diminish over time. Under the assumption of spatially-incoherent ambient noise, an analytical e...

The case studied in the paper proves that thickening the pile cap is an effective seismic retrofit alternative to strengthen a pile group foundation. Unlike the typical seismic retrofitting of foundation, the proposed method eliminates the need to drive long piles into existing bridge substructures, substantially reducing cost, construction time and traffic interruption. The method thickens the...

The increasingly demanding performance requirements trigger the development of new devices to eliminate the limitations concerning the post-earthquake performance of available seismic protection systems. The prerequisite for economical earthquakeresistant bridges is the structures’ capacity to absorb and dissipate a large amount of seismic energy. A widely considered strategy for enhancing this...

In order to mitigate against possible impacts of seismic surveys on baleen whales it is important to know as much as possible about the presence of whales within the vicinity of seismic operations. This study expands on previous work that analyzes single seismic streamer data to locate nearby calling baleen whales with a grid search method that utilizes the propagation angles and relative arriv...

Seismic protective devices in the form of isolation and supplemental damping devices can be effective means in mitigating the seismic responses of structures. The required stiffness and damping values to achieve optimal performance depend on the characteristics of structures and ground motions. Instead of using actively controlled devices, one can select the passive devices to roughly mimic the...