Explore Associations

A camera-trap study in the Peruvian Andes reported a decline in recorded terrestrial mammal and bird activity during the weeks preceding one magnitude 7.0 earthquake, with no animal activity recorded during the final five to seven days. A broader systematic review found that unusual pre-earthquake behavior has been reported across many animal species, including birds, but most reports were retrospective, anecdotal, or lacked adequate baseline observations and controls. Bird detections may also v…

A retrospective study reported changes in statistical properties of acoustic noise recorded within a honey-bee hive during selected periods preceding earthquakes. The authors compared these changes with patterns derived from geomagnetic measurements and interpreted their temporal organization as possible precursor behavior. However, hive acoustics respond to numerous biological, environmental, and operational influences, and the study did not demonstrate that the bees detected an earthquake-prep…

Some studies report changes in groundwater level, temperature, pressure, flow, or chemistry before nearby earthquakes. However, findings are inconsistent and often site-specific, while rainfall, seasonal variation, groundwater pumping, land use, and instrument effects can produce similar changes. This is therefore a reported temporal association, not evidence that groundwater anomalies reliably predict or cause earthquakes.

Published reports describe electric, magnetic, geomagnetic, radio-propagation, and ionospheric anomalies during periods preceding some earthquakes. Proposed explanations include stress-related electrical processes in rock and coupling between the lithosphere, atmosphere, and ionosphere. However, reported signals vary across events, instruments, locations, frequencies, and analytical methods, and similar anomalies may arise from solar and geomagnetic activity, lightning, weather, human technology…

An observational time-series study reported that dairy-cow milk yields varied systematically before a selected set of nearby earthquakes, including a negative association approximately three weeks before the event dates. Milk yield is an objective, routinely collected physiological and productivity measure, but it is influenced by many non-seismic factors. Current evidence supports a reported temporal association only and does not establish causation or reliable earthquake forecasting.

The study reported elevated collective activity among monitored farm animals before some nearby earthquakes while the animals were housed in a stable. The pattern was not detected consistently while the animals grazed on pasture. This is a reported temporal association from a limited observational dataset and does not establish causation or reliable earthquake forecasting.