Palestra de Professor Visitante Dr. Martin Schimmel (Instituto de Ciencias de la Tierra Jaume Almera-CSIC, Barcelona, Espanha)

Palestra de Professor Visitante Dr. Martin Schimmel (Instituto de Ciencias
de la Tierra Jaume Almera-CSIC, Barcelona, Espanha)



i - Local: Auditório do Departamento de Geofísica
ii - Data e hora: 15 de março de 2013, às 1645.

O Dr. Martin Schimmel (Instituto de Ciencias de la Tierra Jaume
Almera-CSIC, Barcelona, Espanha) é sismólogo e está visitando a UFRN
através do Programa Ciência sem Fronteiras. Um
dos objetivos do projeto é explorar as possibilidades de imageamento e
caracterização geofísica utilizando "ruído" sísmico.

Título da palestra: Extração eficiente de sinal do ruido sismico ambiente
utilizando novas metodologias de correlação-cruzada e stacking.

Resumo da palestra: In the seminar, I will summarize the basic concepts
related to ambient noise generation and extraction of empirical Green's
functions from seismic noise. The classical processing flow will be
introduced and I will show how the instantaneous phase coherency can be
used for a more efficient signal extraction from noise cross-correlations.
The instantaneous phase coherence is obtained by analytic signal
processing
and can be employed through the phase cross-correlation and/or through the
time-frequency domain phase-weighted stack. I will explain these methods
and illustrate their benefits and limitations using a synthetic data
analysis. It is shown that both approaches are powerful tools in the
recovery of signals from ambient noise data. I will further show real data
examples where they improve the extraction of P and Rayleigh waves
considering regional and global scale applications. The main part of this
seminar is closely related to research presented in Schimmel, M.,
Stutzmann, E., Gallart, J., Using instantaneous phase coherence for signal
extraction from ambient noise data at a local to a global scale, Geophys.
J. Int., 184, 494-506, 2011.