Earthquake History by Location: Compare and Export USGS Events

No. It queries events already recorded in the USGS catalog. Counts, animations and maximum magnitudes describe that result only. They do not estimate the probability or impact of a future event and cannot determine whether a building or travel plan is safe.

The tool applies the same dates, minimum magnitude and radius to both centers. That makes the query rules explicit, but it does not make detection completeness or tectonic conditions equal. Regions may overlap and the same event can correctly appear in both catalogs.

Both date fields refer to UTC calendar dates. The start is included and the end date is included through its final millisecond. Internally, adjacent query segments use a half-open time interval so events on a boundary are not counted twice.

A response at the 10,000-event page ceiling is split into smaller time intervals and retried. Results are deduplicated by event ID. More than 50,000 events or 15 provider requests for one region produces an explicit error asking you to narrow the query; a partial catalog is not presented as complete.

Monitoring networks and reporting practices change. Small earthquakes were not detected equally in every place or year. The CSV keeps the reported magnitude type, event type and review status rather than implying that all numbers are identical measurements.

Historical responses are cached for one hour, and exports retain the source URL and retrieval time. Catalog events can be revised. Your selected coordinates and filters are sent to the query service; no device location permission is requested and no saved personal location profile is created.