A geology concept defining Earth materials, structures, and processes operating over geologic time. It governs plate interactions, deformation, magmatism, sedimentation, and dating methods used to interpret Earth history. It does not uniquely determine causes without integration of field evidence, measurements, and alternative hypotheses. It supports hazard assessment and resource evaluation by connecting process understanding to observable features. The concept is generally stable, though analytical precision and monitoring improve over time.

Principle

Uncertainty originates from measurement error, natural variability (aleatory), incomplete knowledge or model structure (epistemic) and should be explicitly characterized, propagated and communicated alongside forecasts and assessments.

Demonstration

A probabilistic eruption forecast that reports a 5–20% probability range for eruption within 7 days, with sensitivity bounds derived from alternative model parameterizations and observational noise estimates.

Misapplication

Presenting single‑value forecasts without uncertainty bounds, suppressing uncertainty to appear decisive, or confusing low probability with impossibility when communicating hazards.

Consequence

Explicit treatment and communication of uncertainty improves decision robustness, allows contingency planning across scenarios, and prevents overconfidence in single outcomes.

Reversal

Asserting deterministic certainty about eruptive timing, magnitude or impacts despite insufficient data or untested models, which can lead to inappropriate responses or false reassurances.

Boundary

Covers scientific and epistemic uncertainties associated with observations, models and parameter estimates for active volcanic systems; excludes sociopolitical ambiguity about decisions that may depend on but are distinct from scientific uncertainty.

Semantic Tension

Tension between numerical probability statements produced by formal methods and qualitative expert judgement; both are necessary but can differ in interpretation and usability for stakeholders.

Synthesis

Volcano uncertainty is the explicit representation and communication of limits to knowledge about volcanic behaviour—both inherent variability and incomplete information—managed through probabilistic, interval and qualitative expressions to support prudent decisions.