© ICDP, the International Continental Scientific Drilling Program, 1996-2020

www.icdp-online.org

Rapid Drilling Response

global

revised workshop-proposal: ICDP-2008/13
for the funding-period starting 2008-01-15
by Emily E. Brodsky, James Jiro Mori, Kuofong Ma, Claude Jaupart, Demian Michael Saffer
Abstract
The geometry and mechanical properties of faults are catastrophically altered by earthquakes. The immediate aftermath of an earthquake generates transients as illustrated by afterslip and aftershocks. More precise studies of the temperature, seismic velocity and permeability on causative faults hint at a rich behavior that contains clues to the processes behind the cycle of healing and failure. Key issues that can only be addressed by rapid response include: the energetics of fault slip as reflected in fault friction and heat generation, time-dependent changes in fault zone hydraulic properties and architecture that may play a key role in stress state and conditions at failure, and time-dependent changes in seismic velocity that quantitatively reflect fault healing processes. To date, no measurement of any of these key features has been made immediately after a large earthquake at depth on a fault. Here we propose a workshop to directly address this critical lack of observations. The workshop will take place over three days in Santa Cruz, CA, USA. The agenda will include sessions on candidate borehole experiments and response scenarios. Four focus groups will assess the scientific, site, organizational and technical issues involved in rapid response drilling. The focus group reports will be submitted to Scientific Drilling. These reports can form the backbone of a full rapid response drilling proposal.
Scientific Objectives
  • The goals of the workshop are to evaluate the benefits and risks of a rapid response borehole. Specifically, we aim to assess the requisite geological conditions, depths and speeds necessary to collect data that will definitively answer key questions in earthquake physics. The goals of the rapid response borehole itself are to (1) constrain the fault friction during an earthquake by measuring the residual temperature increase,
  • (2) observe the transient hydrological effects of the earthquake in the fault zone and (3) capture the healing of the fault after an earthquake by measuring the variations in seismic velocity. All three experiments lead to better physical understanding of rupture and the earthquake cycle.
Keywords
Active faults, Earthquakes, ICDP-2008/13, Rapid drilling
Location
global: 0, 0

© ICDP, the International Continental Scientific Drilling Program, 1996-2020

www.icdp-online.org