Options
The Propagation of Seismic Waves in the Presence of Strong Elastic Property Contrasts
Auteur(s)
Saleh, Ramin
Jeyaraj, R.
Milkereit, Bernd
Liu, Q.
Date de parution
2012-12-1
Résumé
In an active underground mine there are many seismic activities taking
place, such as seismic noises, blasts, tremors and microseismic events.
In between the activities, the microseismic events are mainly used for
monitoring purposes. The frequency content of microseismic events can be
up to few KHz, which can result in wavelengths on the order of a few
meters in hard rock environment. In an underground mine, considering the
presence of both small wavelength and strong elastic contrasts, the
simulation of seismic wave propagation is a challenge. With the recent
availability of detailed 3D rock property models of mines, in addition
to the development of efficient numerical techniques (such as Spectral
Element Method (SEM)), and parallel computation facilities, a solution
for such a problem is achievable. Most seismic wave scattering studies
focus on large scales (>1 km) and weak elastic contrasts (velocity
perturbations less than 10%). However, scattering in the presence of
small-scale heterogeneities and large elastic contrasts is an area of
ongoing research. In a mine environment, the presence of strong contrast
discontinuities such as massive ore bodies, tunnels and infrastructure
lead to discontinuities of displacement and/or stress tensor components,
and have significant impact on the propagation of seismic waves. In
order to obtain an accurate image of wave propagation in such a complex
media, it is necessary to consider the presence of these discontinuities
in numerical models. In this study, the effects of such a contrast are
illustrated with 2D/3D modeling and compared with real broadband
3-component seismic data. The real broadband 3-component seismic data
will be obtained in one of the Canadian underground mines in Ontario.
One of the possible scenarios investigated in this study that may
explain the observed complexity in seismic wavefield pattern in hard
rock environments is the effect of near field displacements rather than
far field. Considering the distribution of seismic sensors in a mine and
the presence of seismic events within a mine, the recorded wavefield may
represent a near-field displacement, which is not the case for most of
seismic studies. The role of receiver characterization on the recorded
event near the surface or around fault zones is also investigated. Using
2D/3D modeling, the effects of Vp/Vs variation on vertical and
horizontal components of recorded amplitude has been shown.
place, such as seismic noises, blasts, tremors and microseismic events.
In between the activities, the microseismic events are mainly used for
monitoring purposes. The frequency content of microseismic events can be
up to few KHz, which can result in wavelengths on the order of a few
meters in hard rock environment. In an underground mine, considering the
presence of both small wavelength and strong elastic contrasts, the
simulation of seismic wave propagation is a challenge. With the recent
availability of detailed 3D rock property models of mines, in addition
to the development of efficient numerical techniques (such as Spectral
Element Method (SEM)), and parallel computation facilities, a solution
for such a problem is achievable. Most seismic wave scattering studies
focus on large scales (>1 km) and weak elastic contrasts (velocity
perturbations less than 10%). However, scattering in the presence of
small-scale heterogeneities and large elastic contrasts is an area of
ongoing research. In a mine environment, the presence of strong contrast
discontinuities such as massive ore bodies, tunnels and infrastructure
lead to discontinuities of displacement and/or stress tensor components,
and have significant impact on the propagation of seismic waves. In
order to obtain an accurate image of wave propagation in such a complex
media, it is necessary to consider the presence of these discontinuities
in numerical models. In this study, the effects of such a contrast are
illustrated with 2D/3D modeling and compared with real broadband
3-component seismic data. The real broadband 3-component seismic data
will be obtained in one of the Canadian underground mines in Ontario.
One of the possible scenarios investigated in this study that may
explain the observed complexity in seismic wavefield pattern in hard
rock environments is the effect of near field displacements rather than
far field. Considering the distribution of seismic sensors in a mine and
the presence of seismic events within a mine, the recorded wavefield may
represent a near-field displacement, which is not the case for most of
seismic studies. The role of receiver characterization on the recorded
event near the surface or around fault zones is also investigated. Using
2D/3D modeling, the effects of Vp/Vs variation on vertical and
horizontal components of recorded amplitude has been shown.
Notes
, 2012
Nom de l'événement
AGU Fall Meeting Abstracts
Lieu
San Francisco
Identifiants
Type de publication
conference paper
