Source spectra of seismic hum

Hum Filter: Power-line Noise Eliminator for Shallow Seismic Data

A unique filtering approach designed to eliminating power-line noise on shallow seismic data without affecting the frequency content of signal provides a powerful harmonic noise suppression tool for data acquired with modern large dynamic range recording systems. Amplitudes and phases of sinusoids (functions of power-line noise) present before the first arrivals can be estimated using the Leven...

Dominant source regions of the Earth’s ‘‘hum’’ are coastal

[1] Hum beam power observations using the USArray EarthScope transportable array, combined with infragravity wave observations, show that the dominant source area of the Earth’s hum over the 120–400 s period band during winter months is the Pacific coast of North America, with the western coast of Europe a secondary source region. Correlation of hum with model ocean wave heights indicates that ...

Soft Soil Seismic Design Spectra Including Soil-structure Interaction

Design spectrum is known as an essential tool in earthquake engineering for calculation of maximum (design) responses in a structural system. Soil-structure interaction (SSI), as a phenomenon of coupling of responses of a structure and its underlying soil, was explored after introduction of design spectra and has not been taken into account in developing a design spectrum traditionally. To cons...

Seismic Source Identification Techniques

Analysis of Source Spectra

The purpose of this paper is to present the fundamentally basic aspects of source spectra through the preliminary use of the one-dimensional Haskell source model which assumes a finite fault with a constant rupture velocity. Teleseismic distances are assumed, such that the far field term dominates, allowing the P and S waves emanating from the source to be effectively considered double couple p...