Brian D Kilgore
I design and perform lab experiments investigating; the physics of rock friction and earthquake occurrence, rate- and state-dependent friction, earthquake nucleation, and dynamic earthquake rupture propagation. I am specifically interested in precision wide-bandwidth (DC to 1 MHz) measurements of; position, velocity, acceleration, force, strain and non-destructive ultrasonic testing processes.
Biography
For more information about the labs, including publications, please visit: https://earthquake.usgs.gov/research/eqproc/rockphysics/
For additional publications, please visit: https://www.researchgate.net/profile/Brian_Kilgore
Science and Products
Role of fault gouge during Interaction between hydraulic fracture and a preexisting fracture
Enhanced reservoir connectivity generally requires maximizing the intersection between hydraulic fracture (HF) and preexisting underground natural fractures (NF), while having the hydraulic fracture continue to propagate across the natural fractures. Observations of downhole core samples suggest that these natural fractures are in fact veins...
Mighani, S.; Lockner, David A.; Kilgore, Brian D.; Evans, Brian Interaction between hydraulic fracture and a preexisting fracture under triaxial stress conditions
Enhanced reservoir connectivity generally requires maximizing the intersection between hydraulic fracture (HF) and preexisting underground natural fractures (NF), while having the hydraulic fracture cross the natural fractures (and not arrest). We have studied the interaction between a hydraulic fracture and a polished saw-cut fault. The...
Mighani, Saied; Lockner, David A.; Kilgore, Brian D.; Sheibani, Farrokh; Evans, Brian A wideband magnetoresistive sensor for monitoring dynamic fault slip in laboratory fault friction experiments
A non-contact, wideband method of sensing dynamic fault slip in laboratory geophysical experiments employs an inexpensive magnetoresistive sensor, a small neodymium rare earth magnet, and user built application-specific wideband signal conditioning. The magnetoresistive sensor generates a voltage proportional to the changing angles of magnetic...
Kilgore, Brian D. Rock friction under variable normal stress
This study is to determine the detailed response of shear strength and other fault properties to changes in normal stress at room temperature using dry initially bare rock surfaces of granite at normal stresses between 5 and 7 MPa. Rapid normal stress changes result in gradual, approximately exponential changes in shear resistance with fault...
Kilgore, Brian D.; Beeler, Nicholas M.; Lozos, Julian C.; Oglesby, David The transition from frictional sliding to shear melting in laboratory stick-slip experiments
No abstract available
Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.; Moore, Diane E. Earthquake source properties from instrumented laboratory stick-slip
Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments...
Thomas, Marion Y.; Mitchell, Thomas M.; Bhat, Harsha S.; Kilgore, Brian D.; McGarr, Arthur F.; Beeler, Nicholas M.; Lockner, David A.
Gallery of melt textures developed in Westerly Granite during high-pressure triaxial friction experiments
IntroductionMelting occurred during stick-slip faulting of granite blocks sheared at room-dry, room-temperature conditions in a triaxial apparatus at 200–400 megapascals (MPa) confining pressure. Petrographic examinations of melt textures focused largely on the 400-MPa run products. This report presents an overview of the petrographic data...
Moore, Diane E.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M. A robust calibration technique for acoustic emission systems based on momentum transfer from a ball drop
We describe a technique to estimate the seismic moment of acoustic emissions and other extremely small seismic events. Unlike previous calibration techniques, it does not require modeling of the wave propagation, sensor response, or signal conditioning. Rather, this technique calibrates the recording system as a whole and uses a ball impact as a...
McLaskey, Gregory C.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M. Slip-pulse rupture behavior on a 2 meter granite fault
We describe observations of dynamic rupture events that spontaneously arise on meter-scale laboratory earthquake experiments. While low-frequency slip of the granite sample occurs in a relatively uniform and crack-like manner, instruments capable of detecting high frequency motions show that some parts of the fault slip abruptly (velocity >100...
McLaskey, Gregory C.; Kilgore, Brian D.; Beeler, Nicholas M. Laboratory constraints on models of earthquake recurrence
In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely...
Beeler, Nicholas M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian D.; Goldsby, David L. Laboratory generated M -6 earthquakes
We consider whether mm-scale earthquake-like seismic events generated in laboratory experiments are consistent with our understanding of the physics of larger earthquakes. This work focuses on a population of 48 very small shocks that are foreshocks and aftershocks of stick–slip events occurring on a 2.0 m by 0.4 m simulated strike-slip fault...
McLaskey, Gregory C.; Kilgore, Brian D.; Lockner, David A.; Beeler, Nicholas M. High-frequency imaging of elastic contrast and contact area with implications for naturally observed changes in fault properties
During localized slip of a laboratory fault we simultaneously measure the contact area and the dynamic fault normal elastic stiffness. One objective is to determine conditions where stiffness may be used to infer changes in area of contact during sliding on nontransparent fault surfaces. Slip speeds between 0.01 and 10 µm/s and normal stresses...
Nagata, Kohei; Kilgore, Brian D.; Beeler, Nicholas M.; Nakatani, Masao