BCGS Technical Talk – June 18, 2020

Speaker: Dr. Richard Lynch & Dr. Charlie Beard, Sisprobe

Title: Imaging and Monitoring using Ambient Seismic Noise – Dam Wall Monitoring using Fibre Optic (Distributed Acoustic) Sensor, and Mineral Exploration using Nodes

Date/Time: Thursday, June 18, 2020 @ 4:30pm PST

Location: Online Webinar

Abstract:

While active seismic methods have been used successfully for many decades in mineral and hydrocarbon exploration, passive seismic methods are still in their infancy.  In the past 10 years a popular method in the academic community has been seismic interferometry, in which ambient seismic noise – from traffic, small tremors, ocean waves, etc – is used to create virtual controlled seismic sources.  This method is inexpensive and environmentally friendly since no active seismic equipment is necessary and new ultra-portable seismic nodes can be used to collect the data.  Ambient seismic noise is now being used to construct 3D S-wave velocity images of the subsurface, typically from a few meters down to depths of a few kilometers.  It can also be used to monitor very small velocity changes in the subsurface for applications in dynamic engineered geologic environments, for example CO2 injections, hydrocarbon production and tailings dam wall stability.

This presentation will cover the basic theory of seismic interferometry and how it is used to image and monitor the subsurface.  Two case studies will be shown to illustrate the method: a dam wall in Sweden which is permanently monitored by a Distributed Acoustic Sensing fibre-optic system and a mineral exploration site in Canada where a one month deployment of 1000 seismic nodes was used to image an intrusive body that hosts Cu-Pd mineralisation.

Webinar:

A recording of the webinar is available on Youtube.