• journal_title：Geophysics
• Contributor：Yingping Li ; Chuen H. Cheng ; M. Nafi Toksoz
• Publisher：Society of Exploration Geophysicists
• Date：1998-
• Format：text/html
• Language：en
• Identifier：10.1190/1.1444304
• journal_abbrev：Geophysics
• issn：0016-8033
• volume：63
• issue：1
• firstpage：120
• section：Articles

The hydraulic fracturing technique is an important method for enhancing hydrocarbon recovery, geothermal energy extraction, and solid waste disposal. Determination of the geometry and growth process of a hydraulic fracture zone is important for monitoring and assessing subsurface fractures. A relative-source-location approach, based on a waveform correlation and a grid search method, has been developed to estimate relative hypocenter locations for a cluster of 157 microearthquakes induced by hydraulic fracturing at the Los Alamos Hot Dry Rock (HDR) geothermal site. Among the 157 events, 147 microearthquakes occurred in a tight cluster with a dimension of 40 m, roughly defining a vertical hydraulic fracture zone with an orientation of N40 degrees W. The length, height, and width of the hydraulic fracture zone are estimated to be 40, 35, and 5 m, respectively. Analysis of the spatial-temporal pattern of the induced microearthquakes reveals that the fracture zone grew significantly, averaging 0.2 m/minute in a two-hour period toward the northwest along the fracture zone strike.