Earthquake nucleation and rupture at a range of scales : laboratories, gold mines, and subduction zones

We measured spectral and time-domain properties of seismic events over a size range that spans magnitudes M [approx.] -2 to 8 in order to study earthquake source processes. In addition, we conducted laboratory experiments to study interseismic behaviors that can influence earthquake nucleation and we developed a model of eathquake rupture to explain the scaling behaviors we observe. To bridge the scale gap between laboratory data and global seismic observations, we studied data from five deep gold mines in the Far West Rand region of South Africa. These mines are seismically active due to daily underground blasting and record [approx.] 1000 events per day from -2 =/< M =/< 3+ close to their sources. Frequency-magnitude relations, spatio-temporal clustering relations and observations of seismic spectra provide evidence that there are two types of events that occur in these mines, which we designate as Type A and Type B. Type-A events are fracture-dominated ruptures of previously intact rock and show an upper magnitude cutoff at M [approx.] 0.5. They are tightly clustered in space and time and occur close to active stope faces. They have scaling properties that agree with other studies of fresh-fracturing seismicity in that apparent stress decreases with magnitude and stress drop increases with magnitude.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Richardson, Eliza Bonham, 1974-

Advisor dc:contributor.advisor

• Thomas H. Jordan.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8062

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8062