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8 results on '"Masakale, Thabang"'

1. Frequency–Magnitude Distribution of −3.7 ≤ M W  ≤ 1 Mining-Induced Earthquakes Around a Mining Front and b Value Invariance with Post-Blast Time

Author

Naoi, Makoto, Nakatani, Masao, Horiuchi, Shigeki, Yabe, Yasuo, Philipp, Joachim, Kgarume, Thabang, Morema, Gilbert, Khambule, Sifiso, Masakale, Thabang, Ribeiro, Luiz, Miyakawa, Koji, Watanabe, Atsushi, Otsuki, Kenshiro, Moriya, Hirokazu, Murakami, Osamu, Kawakata, Hironori, Yoshimitsu, Nana, Ward, Anthony, Durrheim, Ray, and Ogasawara, Hiroshi

Published
2014
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2. Unexpectedly frequent occurrence of very small repeating earthquakes (−5.1 ≤M w≤ −3.6) in a South African gold mine: Implications for monitoring intraplate faults

Author

Naoi, Makoto, primary, Nakatani, Masao, additional, Igarashi, Toshihiro, additional, Otsuki, Kenshiro, additional, Yabe, Yasuo, additional, Kgarume, Thabang, additional, Murakami, Osamu, additional, Masakale, Thabang, additional, Ribeiro, Luiz, additional, Ward, Anthony, additional, Moriya, Hirokazu, additional, Kawakata, Hironori, additional, Nakao, Shigeru, additional, Durrheim, Raymond, additional, and Ogasawara, Hiroshi, additional

Published
2015
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3. Steady activity of microfractures on geological faults loaded by mining stress

Author

Naoi, Makoto, primary, Nakatani, Masao, additional, Otsuki, Kenshiro, additional, Yabe, Yasuo, additional, Kgarume, Thabang, additional, Murakami, Osamu, additional, Masakale, Thabang, additional, Ribeiro, Luiz, additional, Ward, Anthony, additional, Moriya, Hirokazu, additional, Kawakata, Hironori, additional, Durrheim, Raymond, additional, and Ogasawara, Hiroshi, additional

Published
2015
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4. Quasi-static slip patch growth to 20 m on a geological fault inferred from acoustic emissions in a South African gold mine

Author

Naoi, Makoto, primary, Nakatani, Masao, additional, Kgarume, Thabang, additional, Khambule, Sifiso, additional, Masakale, Thabang, additional, Ribeiro, Luiz, additional, Philipp, Joachim, additional, Horiuchi, Shigeki, additional, Otsuki, Kenshiro, additional, Miyakawa, Koji, additional, Watanabe, Atsushi, additional, Moriya, Hirokazu, additional, Murakami, Osamu, additional, Yabe, Yasuo, additional, Kawakata, Hironori, additional, Yoshimitsu, Nana, additional, Ward, Anthony, additional, Durrheim, Raymond, additional, and Ogasawara, Hiroshi, additional

Published
2015
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5. Frequency–Magnitude Distribution of −3.7 ≤ M W ≤ 1 Mining-Induced Earthquakes Around a Mining Front and b Value Invariance with Post-Blast Time

Author

Naoi, Makoto, primary, Nakatani, Masao, additional, Horiuchi, Shigeki, additional, Yabe, Yasuo, additional, Philipp, Joachim, additional, Kgarume, Thabang, additional, Morema, Gilbert, additional, Khambule, Sifiso, additional, Masakale, Thabang, additional, Ribeiro, Luiz, additional, Miyakawa, Koji, additional, Watanabe, Atsushi, additional, Otsuki, Kenshiro, additional, Moriya, Hirokazu, additional, Murakami, Osamu, additional, Kawakata, Hironori, additional, Yoshimitsu, Nana, additional, Ward, Anthony, additional, Durrheim, Ray, additional, and Ogasawara, Hiroshi, additional

Published
2013
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7. Unexpectedly frequent occurrence of very small repeating earthquakes (−5.1 ≤ Mw≤ −3.6) in a South African gold mine: Implications for monitoring intraplate faults

Author

Naoi, Makoto, Nakatani, Masao, Igarashi, Toshihiro, Otsuki, Kenshiro, Yabe, Yasuo, Kgarume, Thabang, Murakami, Osamu, Masakale, Thabang, Ribeiro, Luiz, Ward, Anthony, Moriya, Hirokazu, Kawakata, Hironori, Nakao, Shigeru, Durrheim, Raymond, and Ogasawara, Hiroshi

Abstract

We observed very small repeating earthquakes with −5.1 ≤ Mw≤ −3.6 on a geological fault at 1 km depth in a gold mine in South Africa. Of the 851 acoustic emissions that occurred on the fault during the 2 month analysis period, 45% were identified as repeaters on the basis of waveform similarity and relative locations. They occurred steadily at the same location with similar magnitudes, analogous to repeaters at plate boundaries, suggesting that they are repeat ruptures of the same asperity loaded by the surrounding aseismic slip (background creep). Application of the Nadeau and Johnson (1998) empirical formula (NJ formula), which relates the amount of background creep and repeater activity and is well established for plate boundary faults, to the present case yielded an impossibly large estimate of the background creep. This means that the presently studied repeaters were produced more efficiently, for a given amount of background creep, than expected from the NJ formula. When combined with an independently estimated average stress drop of 16 MPa, which is not particularly high, it suggests that the small asperities of the presently studied repeaters had a high seismic coupling (almost unity), in contrast to one physical interpretation of the plate boundary repeaters. The productivity of such repeaters, per unit background creep, is expected to increase strongly as smaller repeaters are considered (∝ Mo−1/3as opposed to Mo−1/6of the NJ formula), which may be usable to estimate very slow creep that may occur on intraplate faults. The smallest repeating earthquakes ever identified as such on geological faultsThey are likely repeat ruptures of asperities induced by creep of the surrounding faultThey repeated much more frequently than those at plate boundaries for a given amount of creep

Published
2015
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8. Frequency-Magnitude Distribution of −3.7 ≤ M ≤ 1 Mining-Induced Earthquakes Around a Mining Front and b Value Invariance with Post-Blast Time.

Author

Naoi, Makoto, Nakatani, Masao, Horiuchi, Shigeki, Yabe, Yasuo, Philipp, Joachim, Kgarume, Thabang, Morema, Gilbert, Khambule, Sifiso, Masakale, Thabang, Ribeiro, Luiz, Miyakawa, Koji, Watanabe, Atsushi, Otsuki, Kenshiro, Moriya, Hirokazu, Murakami, Osamu, Kawakata, Hironori, Yoshimitsu, Nana, Ward, Anthony, Durrheim, Ray, and Ogasawara, Hiroshi

Subjects
EARTHQUAKE magnitude, ACOUSTIC emission, GOLD mining, BLASTING, SEISMOLOGY
Abstract

We investigated frequency-magnitude distribution (FMD) of acoustic emissions (AE) occurring near an active mining front in a South African gold mine, using a catalog developed from an AE network, which is capable of detecting AEs down to M −5. When records of blasts were removed, FMDs of AEs obeyed a Gutenberg−Richter law with similar b values, not depending on post-blasting time from the initial 1-min interval through more than 30 h. This result denies a suggestion in a previous study ( Richardson and Jordan Bull Seismol Soc Am, 92:1766-1782, ) that new fractures generated by blasting disturb the size distribution of background events, which they interpreted as slip events on existing weak planes. Our AE catalog showed that the GR law with b ∼ 1.2 was valid between M −3.7 and 0 for AEs around the mining front. Further, using the mine's seismic catalog, which covers a longer time period of the same area, we could extend the validity range of the GR law with the same b value up to M 1. [ABSTRACT FROM AUTHOR]

Published
2014
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