Understand USGS Earthquake Alert and Tsunami Fields

Earthquake metadata contains several fields that look like simple severity labels but serve different purposes. The USGS Earthquake Scraper keeps them separate so downstream systems do not collapse them into one misleading signal.

Preserve the meaning of each indicator

alert is the PAGER alert color when supplied. significance is a numeric USGS ranking measure. felt_reports counts submitted responses. cdi represents community intensity, while mmi is instrumental intensity. tsunami is a catalog flag, not a complete warning bulletin.

{"minMagnitude":5,"alertLevel":"yellow","orderBy":"time","maxResults":100}

An alert-level filter is useful for monitoring, but do not equate an absent alert with a harmless event. Values can be unavailable, preliminary, or revised. Preserve nulls and the event update time. When a record changes, display both the new official value and the fact that it was revised.

For newsroom or risk workflows, create separate rules: one for new high-magnitude events near relevant locations, another for PAGER alert changes, and another for official tsunami communications outside this dataset. Include event title, time, coordinates, depth, status, and source URL in every notification.

Never create an evacuation instruction from the dataset. The tsunami field is a prompt to consult official warning centers, not a replacement for them. Similarly, felt reports reflect reporting participation and population as well as shaking. Clear labels and source links keep a convenient automated feed from becoming an overconfident safety product.