Predicting maximum possible earthquakes triggered by massive subsurface interventions is an
urgent practical problem. To address this problem, we propose to distinguish between the
probability of well-controlled induced seismic events and the probability of triggered tectonic
earthquakes with out-of-control ruptures extending well beyond the operating domain. To put this
approach into practice, we introduce the concept of the seismotectonic continuum and combine it
with the seismogenic index model and the lower-bound statistics of the frequency-magnitude
distribution of induced earthquakes. On this basis, we propose to calculate and monitor the worst-
case probability of triggering a large-magnitude tectonic earthquake in a continuum. To illustrate
our approach, we consider several case studies including the classical case study of the Denver
earthquake series of 1962-68, the Groningen gas field and the Pohang geothermal site in South
Korea.