Frequency-Magnitude Characteristics Down to Magnitude -4.4 for Induced Seismicity Recorded at Mponeng Gold Mine, South Africa

This article aims to investigate the frequency-magnitude characteristics and lower magnitude limits of the microseismic catalog recorded with a seismic network sensitive to high frequencies at Mponeng mine, South Africa. The network, composed of one three-component accelerometer and eight acoustic emission sensors, is located at a depth of 3.5 km below the surface and covers the limited volume of approximately 300×300×300 m. The three-component accelerometer was used to estimate the moment magnitude for the limited number of 135 events ( M w ranged from -4.1 to -0.3) well recorded by the network. We use the relation between the moment magnitude estimated from accelerometer data and radiated energy/moment magnitude estimated from acoustic emission sensors to extend the catalog to lower magnitudes. The magnitude of completeness of selected spatiotemporal subsets of the catalog was estimated for: (1) an aftershock sequence of an M w 1.9 event that occurred approximately 30 m from the network, and (2) postblasting activity during working days, located more than 80 m from the network. The data follow the Gutenberg–Richter (GR) frequency-magnitude relationship with no visible deviation from self-similar behavior of seismicity between M w -4.4 and -1.9 for the aftershock sequence and between -3.5 and -1.5 for the postblasting dataset. We estimated the magnitude of completeness of selected subset as low as -4.3 ( b =1.26) for the aftershock sequence and -3.4 ( b =1.17) for the postblasting activity. Differences in magnitude of completeness are attributed to location of recorded activity and site effects.

[1]  Gregory C. Beroza,et al.  Does apparent stress vary with earthquake size? , 2001 .

[2]  J. Dieterich.  Modeling of rock friction: 1. Experimental results and constitutive equations , 1979 .

[3]  M. Wyss,et al.  Minimum Magnitude of Completeness in Earthquake Catalogs: Examples from Alaska, the Western United States, and Japan , 2000 .

[4]  Yoshiaki Ida,et al.  The maximum acceleration of seismic ground motion , 1973 .

[5]  R. P. Young,et al.  Premonitory acoustic emissions and stick‐slip in natural and smooth‐faulted Westerly granite , 2009 .

[6]  James R. Rice,et al.  Seismic Fault Rheology and Earthquake Dynamics , 2006 .

[7]  H. Bungum,et al.  Source Parameters and Scaling Relations for Mining-Related Seismicity within the Pyhäsalmi Ore Mine, Finland , 2005 .

[8]  Hiroshi Ogasawara,et al.  Observation of numerous aftershocks of an Mw 1.9 earthquake with an AE network installed in a deep gold mine in South Africa , 2009 .

[9]  T. Jordan,et al.  Seismicity in Deep Gold Mines of South Africa: Implications for Tectonic Earthquakes , 2002 .

[10]  A. McGarr,et al.  On relating apparent stress to the stress causing earthquake fault slip , 1999 .

[11]  J. A. Snoke.  Stable determination of (Brune) stress drops , 1986 .

[12]  Keiiti Aki,et al.  Magnitude‐frequency relation for small earthquakes: A clue to the origin of ƒmax of large earthquakes , 1987 .

[13]  Hans-Peter Harjes,et al.  Source parameters of injection-induced microearthquakes at 9 km depth at the KTB Deep Drilling site, Germany , 1998, Bulletin of the Seismological Society of America.

[14]  T. Utsu.  A method for determining the value of b in a formula log n=a-bM showing the magnitude frequency relation for earthquakes , 1965 .

[15]  W. Brace,et al.  Stick-Slip as a Mechanism for Earthquakes , 1966, Science.

[16]  J. Dieterich.  Earthquake nucleation on faults with rate-and state-dependent strength , 1992 .

[17]  H. Kanamori,et al.  A moment magnitude scale , 1979 .

[18]  M. Johnston,et al.  Extension of Gutenberg‐Richter distribution to MW −1.3, no lower limit in sight , 2009 .

[19]  S. J. Gibowicz,et al.  Source parameters of seismic events at the Underground Research Laboratory in Manitoba, Canada: Scaling relations for events with moment magnitude smaller than −2 , 1991 .

[20]  Rachel E. Abercrombie,et al.  Earthquake source scaling relationships from −1 to 5 ML using seismograms recorded at 2.5‐km depth , 1995 .

[21]  Gerd Manthei,et al.  Characterization of Acoustic Emission Sources in a Rock Salt Specimen under Triaxial Compression , 2005 .

[22]  Jörn Davidsen,et al.  Scaling and universality in rock fracture. , 2007, Physical review letters.

[23]  D. S. Collins,et al.  High-resolution Mechanics of a Microearthquake Sequence , 2002 .