Significant earthquakes: weekly impact digest

The trailing 7 complete days (UTC) of magnitude 4.5+ earthquakes from the USGS ANSS Comprehensive Catalog, transformed into a ranked impact digest (typically 50-150 events/week). Each row is one earthquake: origin time, epicenter, depth, magnitude, a region key parsed from the USGS place string, conservatively resolved country (canonical name + ISO alpha-3; empty for offshore sequences where no country can be verified), tsunami flag, felt-report count, USGS significance, review status, aftershock-sequence membership (sequence_id = the mainshock's event id, is_mainshock, event count), a documented 0-100 impact score and its rank (100*(0.50*energy_norm + 0.15*shallow + 0.15*felt_norm + 0.10*tsunami + 0.10*recency)), per-row USGS detail URL, and a row hash. Primary key: event_id. Cadence: weekly; the as_of date is the window end, so identical input produces an identical content hash. Caveats: USGS revises events after publication (updated_utc tracks revisions); detection completeness varies by region; country resolution is best-effort and deliberately null-heavy offshore; 'Georgia' resolves to null (state/country ambiguity). USGS data is U.S. public domain — commercial_use = yes. Sample use: order by impact_rank for the week's most significant quakes, or filter is_mainshock = 1 for one row per sequence.