Emmy-Noether-Projekt "Brückenschlag zwischen Geodäsie und Seismologie"

Characterization of small local noise sources with array seismology

Ritter, J. R. R. and H. Sudhaus (2007)

Near Surface Geophysics 5(4): 253-261.

DOI: 10.3997/1873-0604.2007007

earthdoc.org
 

Abstract:

Seismic noise is often regarded as a stochastic, incoherent and unwanted signal. However, at a closer look, noise also contains coherent signals which can be used to characterize its sources and/ or the subsurface.

Here, we propose the use of array seismological methods for engineering purposes to locate and identify small, local noise sources. A detailed knowledge of noise sources enables appropriate measures to be taken to mitigate unwanted noise effects.

As a case study, we report results from a temporary array of ten seismic broadband stations which were installed at the building site of a high-precision physics laboratory.

Standard analyses of power spectra and amplitude measurements indicate that the highest noise amplitudes are caused by heavy trucks passing by. Burst-like coherent waves, excited by vehicles, appear to have a recurring pattern. Using array techniques, we were able to measure the slowness and backazimuth of the coherent arrivals.

These could be identified as Rayleigh waves generated at small pot-holes and bumps of a near-by road and were found to propagate with a speed of 130–200 m/s.

Geofon

SRCMOD - Database

    • Inversion modelling of geodetic (InSAR) and seismological data
    • earthquake slip complexity and co-seismic rupture history
    • Connecting earthquake models to observations
    • Kinematic earthquake source inversion

     

    In my research i am interested in how earthquakes ruptures behave and how and why earthquakes develop complex ruptures in space and time. Complex means that the earthquake ruptures e.g. across multiple fault planes with different geometries or slows down/accelerates in different areas. We know that earthquakes rupture with different degrees of complexity and we believe that larger earthquake rupture in more complex ways. This would however violate the common assumption of self-similarity of earthquakes across magnitudes. Often the choice of the modeled degree of complexity is however dependent on expert knowledge. Therefore i am looking for data driven ways to help us evaluate possibly rupture segmentation. Also I focus on small to medium sized earthquakes to investigate if we can resolve any complex ruptures from them or if they do not exhibit such behavior. I am using InSAR, GPS and seismological data.

    To asses the evolution of an earthquake rupture in time i have developed a multi-array backprojection code, which is available on github: Palantiri