Post Slack safety checks for Google Sheets sites near USGS earthquakes

## Earthquake near a site? Ask who is safe, at once Every 5 minutes the workflow reads the free USGS real-time earthquake feed (no key). For every site in your Sites tab (name, latitude, longitude, contact), code computes the distance from the epicentre and posts a safety-check message in Slack when the magnitude is at or above your limit and the site is within your radius. The contact is mentioned; people reply in the thread. No AI is used. ### How it works 1. Read the Sites tab and the USGS feed (default: M4.5+ of the past hour). 2. Code checks each earthquake against each site (distance and magnitude, per-site limits optional). A wrong coordinate stops the run with a clear message instead of dropping the site. 3. One Slack message per earthquake lists the sites nearby, closest first. 4. The Alerts tab stores earthquake + site, so the same pair is never sent twice. ### Setup 1. Blank Google Sheet: paste its ID in Spreadsheet ID, run Run once, select the sheet in the Google Sheets nodes. 2. Fill the Sites tab: site, lat, lon (right-click the place in Google Maps to copy them), contact (a Slack member ID mentions them). 3. Pick a Slack channel. Set the limits, language and time zone in Config. Publish. ### Note Magnitude is not local shaking intensity. Use it as a trigger to ask, not as a damage report.