This tool builds one candidate rupture scenario per fault system from a set of trench paleoearthquake ages (TPAs)
using a sweep-line approach adapted from the classical geometric algorithm for reporting interval intersections
(Bentley & Ottmann (1979)).
Instead of segments in a plane, the "intervals" here are each trench's dated event windows (older/younger bound);
the sweep advances from the oldest active bound to the youngest, and at each step looks for the largest set of
trenches whose current TPA windows overlap. That overlap becomes a candidate fault event age (FEA), following the
rule-based reconstruction scheme of
Lombardi et al. (2026),
the paper describing the official POPE software package this tool reimplements.
Three rules keep the reconstruction consistent: every TPA must eventually be assigned to some FEA (R1); each TPA
can define at most one FEA (R2), so once a trench's oldest active event has been consumed by a bound it touches,
the sweep advances to that trench's next event; and two TPAs from the same trench can never be forced into the
same FEA (R3), since a single trench cannot record two separate ruptures as if they were one earthquake. After the
sweep completes, any FEAs left temporally overlapping are merged in a consolidation pass — but only when the merge
would not itself violate R3 — following the same general chronology-modeling logic used to reconstruct regional
earthquake recurrence and "earthquake storm" sequences from paleoseismic trench data
(Cinti et al. (2021)).
The official POPE package enumerates every rupture scenario consistent with the input data for expert review and
probabilistic assessment of future fault behavior
(Lombardi et al. (2025));
this browser tool instead computes a single self-consistent candidate scenario per fault — useful for a quick
first look at a dataset before turning to the full package for exhaustive, citable scenario enumeration.