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Towards a Transparent Earth. S.D. Glaser, UC, Berkeley W. Roggenthen , SDSMT L.R. Johnson, E.L. Majer , LBNL. Install an acoustic “microscope” surrounding the Homestake workings – 1 st NSF funded DUSEL research. signal. Deep is Quiet, and Quiet is Good. noise.

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Towards a Transparent Earth

S.D. Glaser, UC, Berkeley

W. Roggenthen, SDSMT

L.R. Johnson, E.L. Majer, LBNL

Install an acoustic “microscope” surrounding the Homestake workings – 1st NSF funded DUSEL research

signal

Deep is Quiet, and Quiet is Good

noise

  • Develop deep in-situ seismic observatory for rapid imaging of dynamical geo-processes at depth.

  • Provide rock mass dynamics and safety information to miners and tunnelers

  • Provide an infrastructure for all earth scientists

  • Improve ability to detect and characterize underground structures and activity


Seismic Imaging of Subsurface Stress

  • The time-varying stress field at depth is perhaps the most crucial parameter for understanding the earthquake triggering process.

  • The Speed of Seismic Waves is a Measures of Stress in Rocks. This holds at seismogenic depth and can be used as a “stress meter”.

  • Why at Homestake?

    Stress changes at seismogenic depth could be more difficult to observe with conventional surface instruments.

    Temperature variation at surface is a large noise source in the electronics.

    Deep observation could avoid surface environmental effects, such as precipitation.

    Need a deep natural experiment site that bridges laboratory study and large scale seismic experiment.

    FenglinNiu Rice University

    P. G. Silver, Carnegie Institution of Washington

    T. Daley, Lawrence Berkeley National Lab


    Erik c westman virginia tech

    TOMOGRAPHIC IMAGING OF STRESS-REDISTRIBUTION FOR PREDICTION OF CATASTROPHIC ROCK MASS FAILURE

    Stress concentration prior to pillar failure caused by slip along a discontinuity or by overburden stress (in a solid rock mass)

    Multiple pillars (of differing dimension) constructed at multiple depths; may include discontinuities

    Seismic tomography used to image stress-induced density contrasts within rock mass, allowing stress level to be determined and failure projected

    Catastrophic failure extends to all aspects of rock mechanics including tunnels, mines, rock slopes, earthquakes, waste repositories, and bridge and dam abutments

    Accomplishing the ultimate goal of predicting these catastrophic failures will result in significantly reduced fatalities, lowered construction costs, and increased environmental protection.

    Erik C. Westman , Virginia Tech

    Rock failures are associated with the redistribution and concentration of stresses from mine excavations

    To predict rock failure, monitor the redistribution of stresses within the rock.

    Use tomograms of seismic stress field toimage redistribution of stress

    Shown clearly in the laboratory but limited testing at the field scale.

    This experiment will enhance miner’s life safety

    This experiment will put the method of imaging stress-induced changes within rock masses on a sound theoretical and practical basis. Itrequires a DUSEL, as deep, long-term, dedicated access is not available at current underground tests sites.


    Fracto em emissions in rocks

    Conduction Modulation

    Charge acceleration

    Piezoelectricity

    Mech. wave

    =0

    EM-wave

    Microseismicity sensor network

    ü

    E

    Antennae network

    VA

    P

    P=0

    + + + + +

    B

    - - - - - -

    VB

    Fracture current

    Fracture-Atm. Interaction

    Charge separation

    F

    F

    EM emissions

    E(t)

    EM emission

    t

    i(t)

    Fracto-emission generating fault

    Diffusion of electrically neutral gas

    F

    F

    Fracto-EM Emissions in Rocks

    Dante Fratta, University of Wisconsin-Madison

    DUSEL provides unique research opportunity for the development of a new engineering monitoring system based on the complementary interpretation of microseismic and EM emissions in a quiet electrical environment – Homestake mine


    Geoinformation processing of multi‐dimensional spatial

    monitoring data

    Christian D. Klose, Columbia University

    Monitoring the Earth's system

    from a global perspective.

    Geophysical Data

    Classify multi-dimensional and complex data

    Geological Data

    Interpret & Predict

    in areas of interest

    - zones of weakness

    - seismic events

    - zones of fluid migrations

    Applied data interpretation methods are based on Artificial Intelligence