Relating high-resolution tilt measurements to the source displacement of an M2.2 event located at Mponeng gold mine

Japanese-German research at Mponeng gold mine, South Africa

A unique experiment, called JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), involved the installation and monitoring of several sensitive seismic instruments from 2007 to 2009 at Mponeng gold mine, South Africa (Figure 1).


 JAGUARS was a joint project of the University of Tokyo, Tohoku University, Ritsumeikan University (Japan), GFZ German Research Center for Geosciences, Gesellschaft für Materialprüfung und Geophysik (Germany), Seismogen CC, AngloGold Ashanti Ltd., ISS International, and the Council for Scientific and Industrial Research (CSIR, South Japanese-German research at Mponeng gold mine, South Africa A unique experiment, called JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), involved the installation and monitoring of several sensitive seismic instruments from 2007 to 2009 at Mponeng gold mine, South Africa (Figure 1). JAGUARS was a joint project of the University of Tokyo, Tohoku University, Ritsumeikan University (Japan), GFZ German Research Center for Geosciences, Gesellschaft für Materialprüfung und Geophysik (Germany), Seismogen CC, AngloGold Ashanti Ltd., ISS International, and the Council for Scientific and Industrial Research (CSIR, SouthAfrica) (Naoi et al., 2011). The instruments
installed included acoustic emission (AE) sensors, strain meters, and an accelerometer
(Figure 2a). In addition, two high-resolution tiltmeters (Figure 2b), managed by the CSIR,
were also installed. The installation site was located 90 m below a dip pillar at a depth of approximately 3270 m below surface. The high-resolution tiltmeters were installed in a cubby close to a large dyke, termed the Pink and Green Dyke (Figure 2), while the other seismic sensors were installed within and around the dyke (Figure 2a).


The M2.2 event located in close proximity to the monitoring site

Data acquisition started in June 2007 and ended in January 2009, during which time an M2.2 event occurred on 27 December 2007 with the main shock less than 50 m away from the monitoring site. The event was recorded by both the CSIR tiltmeters and JAGUARS network.
The main shock of the M2.2 event, as determined by the in-mine seismic network, lies within the dyke, and 60 per cent of the more than 20 000 aftershocks located by the AE network (Yabe et al., 2009; Naoi et al., 2011) are associated with the main rupture and are also situated within the dyke (Figure 3). This is in contrast to what is intuitively expected, where in-mine rupture or failure generally occurs along structural weaknesses, such as a  Dyke-quartzite (host rock) boundary...

Relating high-resolution tilt measurements to the source displacement of an M2.2 event located at Mponeng gold mine

by P. Share*, A. Milev*, R. Durrheim*, J. Kuijpers, and H. Ogasawara*§



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