fix(earthquakes): reject malformed feature properties

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 Earthquake refreshes validate the complete feed and construct replacement entities before clearing the previous snapshot. Malformed rows and duplicate rendered IDs retain the last good entities, overlays, count and timestamp and report a malformed response; unknown magnitude is excluded from M2.5+ rendering.
 
+Non-object or array-valued properties reject the response instead of being treated as an unknown magnitude.
+
 This changelog records public product changes. For the authoritative description
 of current runtime behavior, see [`docs/CURRENT-STATE.md`](docs/CURRENT-STATE.md).
 

docs/CURRENT-STATE.md

@@ -4,6 +4,8 @@
 
 Earthquake refreshes validate the complete feed and construct replacement entities before clearing the previous snapshot. Malformed rows and duplicate rendered IDs retain the last good entities, overlays, count and timestamp and report a malformed response; unknown magnitude is excluded from M2.5+ rendering.
 
+Non-object or array-valued properties reject the response instead of being treated as an unknown magnitude.
+
 Updated: August 24, 2026
 
 ## Installations and map-source guidance

src/data/earthquakes.js

@@ -130,6 +130,7 @@ export function normalizeEarthquakeSnapshot(geojson) {
     const coordinates = feature?.geometry?.coordinates;
     const properties = feature?.properties;
     if (!Array.isArray(coordinates) || coordinates.length < 2 || !properties
+      || typeof properties !== 'object' || Array.isArray(properties)
       || (feature.geometry.type != null && feature.geometry.type !== 'Point')) return null;
     const [lon, lat, depthKm] = coordinates;
     const mag = properties.mag;

src/data/earthquakes.test.mjs

@@ -359,6 +359,19 @@ test('malformed earthquake refresh preserves entities, overlays, count and times
     assert.equal(await layer.update(viewer), true);
     const entity = dataSources[0].entities.values[0];
     const stats = layer.getStats();
+    for (const properties of ['invalid', 123, [], true]) {
+      const bad = { ...good, id: 'bad-properties', properties };
+      for (const features of [[bad], [good, bad]]) {
+        respond(features);
+        assert.equal(await layer.update(viewer), false);
+        assert.equal(dataSources[0].entities.values.length, 1);
+        assert.equal(dataSources[0].entities.values[0], entity);
+        assert.equal(layer.getStats().count, stats.count);
+        assert.equal(layer.getStats().lastUpdate, stats.lastUpdate);
+        assert.equal(layer.getStats().error, 'Malformed USGS response');
+        assert.equal(publications.length, 1);
+      }
+    }
     for (const bad of [null, { ...good, geometry: null },
       { ...good, geometry: { type: 'LineString', coordinates: [1, 2] } },
       { ...good, geometry: { coordinates: [181, 20] } },