de Beer, W, William, R, Prahastudhi, S & de Beer, J 2026, 'Trigger action response development I: the use of event activity rates to assess re-entry times in caving', in A van As, D Cumming-Potvin & J Wesseloo (eds), Caving 2026: Proceedings of the Sixth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-10, https://doi.org/10.36487/ACG_repo/2645_45 (https://papers.acg.uwa.edu.au/p/2645_45_de_Beer/) Abstract: The seismic response following production blasts or large seismic events differs from location to location in a mine (intra-mine) and from mine to mine (inter-mine). When developing trigger action response plans (TARPs), a blanket approach, where the same settings are used for all locations, is inadvisable – areas should be assessed individually. Operators usually focus on a work domain, often an irregular two-dimensional shape defined in plan view. Care should also be taken in the determination of a monitoring domain which contains the work domain, and accounts for the impacts of seismic events at a distance. One of the commonly used seismic parameter for TARP development is the seismic activity rate. We present a workflow to determine monitoring domains and use a seismic system-agnostic Python tool to rapidly assess decay rates for many areas in a mine over arbitrary periods. Keywords: seismic activity rate, TARP, monitoring domain, work domain, re-entry