diff --git a/src/central/adapters/usgs_quake.py b/src/central/adapters/usgs_quake.py
new file mode 100644
index 0000000..b908323
--- /dev/null
+++ b/src/central/adapters/usgs_quake.py
@@ -0,0 +1,400 @@
+"""USGS Earthquake Hazards Program adapter."""
+
+import logging
+import sqlite3
+from collections.abc import AsyncIterator
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+
+import aiohttp
+from shapely.geometry import Point, box as shapely_box
+from tenacity import (
+    retry,
+    stop_after_attempt,
+    wait_exponential_jitter,
+    retry_if_exception_type,
+)
+
+from central.adapter import SourceAdapter
+from central.config_models import AdapterConfig, RegionConfig
+from central.config_store import ConfigStore
+from central.models import Event, Geo
+
+logger = logging.getLogger(__name__)
+
+# USGS GeoJSON feed base URL
+USGS_FEED_BASE = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary"
+
+# Valid feed options
+VALID_FEEDS = {"all_hour", "all_day", "all_week", "all_month"}
+
+
+def magnitude_tier(mag: float) -> str:
+    """Classify magnitude into USGS-style tier."""
+    if mag < 3.0:
+        return "minor"
+    if mag < 4.0:
+        return "light"
+    if mag < 5.0:
+        return "moderate"
+    if mag < 6.0:
+        return "strong"
+    if mag < 7.0:
+        return "major"
+    return "great"
+
+
+def magnitude_to_severity(mag: float) -> int:
+    """Map magnitude to severity level (0-5)."""
+    if mag < 3.0:
+        return 0
+    if mag < 4.0:
+        return 1
+    if mag < 5.0:
+        return 2
+    if mag < 6.0:
+        return 3
+    if mag < 7.0:
+        return 4
+    return 5
+
+
+class USGSQuakeAdapter(SourceAdapter):
+    """USGS Earthquake Hazards Program adapter."""
+
+    name = "usgs_quake"
+
+    def __init__(
+        self,
+        config: AdapterConfig,
+        config_store: ConfigStore,  # Unused, accepted for signature uniformity
+        cursor_db_path: Path,
+    ) -> None:
+        self._cursor_db_path = cursor_db_path
+        self._session: aiohttp.ClientSession | None = None
+        self._db: sqlite3.Connection | None = None
+
+        # Extract settings from config
+        self._feed: str = config.settings.get("feed", "all_hour")
+        if self._feed not in VALID_FEEDS:
+            logger.warning(
+                "Invalid feed setting, using all_hour",
+                extra={"feed": self._feed, "valid": list(VALID_FEEDS)},
+            )
+            self._feed = "all_hour"
+
+        # Parse region from settings
+        region_dict = config.settings.get("region")
+        if region_dict:
+            self.region: RegionConfig | None = RegionConfig(**region_dict)
+            self._region_box = shapely_box(
+                self.region.west,
+                self.region.south,
+                self.region.east,
+                self.region.north,
+            )
+        else:
+            self.region = None
+            self._region_box = None
+
+    async def apply_config(self, new_config: AdapterConfig) -> None:
+        """Apply new configuration from hot-reload."""
+        # Update feed
+        new_feed = new_config.settings.get("feed", "all_hour")
+        if new_feed in VALID_FEEDS:
+            self._feed = new_feed
+        else:
+            logger.warning(
+                "Invalid feed in new config, keeping current",
+                extra={"new_feed": new_feed, "current": self._feed},
+            )
+
+        # Update region
+        region_dict = new_config.settings.get("region")
+        if region_dict:
+            self.region = RegionConfig(**region_dict)
+            self._region_box = shapely_box(
+                self.region.west,
+                self.region.south,
+                self.region.east,
+                self.region.north,
+            )
+        else:
+            self.region = None
+            self._region_box = None
+
+        logger.info(
+            "USGS quake config applied",
+            extra={
+                "region": region_dict,
+                "feed": self._feed,
+            },
+        )
+
+    async def startup(self) -> None:
+        """Initialize HTTP session and dedup tracker."""
+        # Initialize HTTP session
+        self._session = aiohttp.ClientSession(
+            headers={"User-Agent": "Central/1.0 (earthquake monitoring)"},
+            timeout=aiohttp.ClientTimeout(total=30),
+        )
+
+        # Initialize dedup tracker (shared sqlite DB)
+        self._db = sqlite3.connect(str(self._cursor_db_path))
+        self._db.execute("""
+            CREATE TABLE IF NOT EXISTS published_ids (
+                adapter TEXT NOT NULL,
+                event_id TEXT NOT NULL,
+                first_seen TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                last_seen TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+                PRIMARY KEY (adapter, event_id)
+            )
+        """)
+        self._db.execute("""
+            CREATE INDEX IF NOT EXISTS published_ids_last_seen
+            ON published_ids (last_seen)
+        """)
+        self._db.commit()
+
+        # Sweep old entries on startup (7 days for quakes)
+        self.sweep_old_ids()
+
+        logger.info(
+            "USGS quake adapter started",
+            extra={
+                "region": {
+                    "north": self.region.north,
+                    "south": self.region.south,
+                    "east": self.region.east,
+                    "west": self.region.west,
+                } if self.region else None,
+                "feed": self._feed,
+            },
+        )
+
+    async def shutdown(self) -> None:
+        """Close HTTP session and database."""
+        if self._session:
+            await self._session.close()
+            self._session = None
+        if self._db:
+            self._db.close()
+            self._db = None
+        logger.info("USGS quake adapter shut down")
+
+    def is_published(self, event_id: str) -> bool:
+        """Check if an event has already been published."""
+        if not self._db:
+            return False
+        cur = self._db.execute(
+            "SELECT 1 FROM published_ids WHERE adapter = ? AND event_id = ?",
+            (self.name, event_id),
+        )
+        return cur.fetchone() is not None
+
+    def mark_published(self, event_id: str) -> None:
+        """Mark an event as published."""
+        if not self._db:
+            return
+        self._db.execute(
+            """
+            INSERT INTO published_ids (adapter, event_id, first_seen, last_seen)
+            VALUES (?, ?, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
+            ON CONFLICT (adapter, event_id) DO UPDATE SET
+                last_seen = CURRENT_TIMESTAMP
+            """,
+            (self.name, event_id),
+        )
+        self._db.commit()
+
+    def sweep_old_ids(self) -> int:
+        """Remove published_ids older than 7 days. Returns count deleted."""
+        if not self._db:
+            return 0
+        cur = self._db.execute(
+            "DELETE FROM published_ids WHERE adapter = ? AND last_seen < datetime('now', '-7 days')",
+            (self.name,),
+        )
+        self._db.commit()
+        count = cur.rowcount
+        if count > 0:
+            logger.info("USGS quake swept old dedup entries", extra={"count": count})
+        return count
+
+    def _build_url(self) -> str:
+        """Build USGS GeoJSON feed URL."""
+        return f"{USGS_FEED_BASE}/{self._feed}.geojson"
+
+    @retry(
+        stop=stop_after_attempt(3),
+        wait=wait_exponential_jitter(initial=1, max=15),
+        retry=retry_if_exception_type((aiohttp.ClientError,)),
+        reraise=True,
+    )
+    async def _fetch_geojson(self) -> dict[str, Any]:
+        """Fetch GeoJSON data from USGS."""
+        if not self._session:
+            raise RuntimeError("Session not initialized")
+
+        url = self._build_url()
+        async with self._session.get(url) as resp:
+            resp.raise_for_status()
+            return await resp.json()
+
+    def _point_in_region(self, lon: float, lat: float) -> bool:
+        """Check if point intersects region bbox using shapely."""
+        if self._region_box is None:
+            return True
+        point = Point(lon, lat)
+        return self._region_box.intersects(point)
+
+    def _feature_to_event(self, feature: dict[str, Any]) -> Event | None:
+        """Convert a GeoJSON feature to an Event."""
+        props = feature.get("properties", {})
+        geometry = feature.get("geometry", {})
+        coords = geometry.get("coordinates", [])
+
+        # Validate required fields
+        event_id = feature.get("id")
+        if not event_id:
+            logger.warning("Feature missing id", extra={"properties": props})
+            return None
+
+        # Get magnitude - skip if null/missing (PM decision)
+        mag = props.get("mag")
+        if mag is None:
+            logger.debug(
+                "Skipping event with null magnitude",
+                extra={"id": event_id, "place": props.get("place")},
+            )
+            return None
+
+        try:
+            mag = float(mag)
+        except (TypeError, ValueError):
+            logger.warning(
+                "Invalid magnitude value",
+                extra={"id": event_id, "mag": mag},
+            )
+            return None
+
+        # Get coordinates [lon, lat, depth]
+        if len(coords) < 2:
+            logger.warning("Feature missing coordinates", extra={"id": event_id})
+            return None
+
+        lon, lat = coords[0], coords[1]
+        depth = coords[2] if len(coords) > 2 else None
+
+        # Region filter
+        if not self._point_in_region(lon, lat):
+            return None
+
+        # Parse event time (milliseconds since epoch)
+        time_ms = props.get("time")
+        if time_ms is not None:
+            try:
+                event_time = datetime.fromtimestamp(time_ms / 1000, tz=timezone.utc)
+            except (TypeError, ValueError, OSError):
+                event_time = datetime.now(timezone.utc)
+        else:
+            event_time = datetime.now(timezone.utc)
+
+        # Build tier and severity
+        tier = magnitude_tier(mag)
+        severity = magnitude_to_severity(mag)
+
+        # Build geo
+        geo = Geo(
+            centroid=(lon, lat),
+            bbox=(lon, lat, lon, lat),
+            regions=[],
+            primary_region=None,
+        )
+
+        # Build data payload
+        data = {
+            "magnitude": mag,
+            "place": props.get("place"),
+            "time_ms": time_ms,
+            "updated_ms": props.get("updated"),
+            "tz": props.get("tz"),
+            "url": props.get("url"),
+            "detail": props.get("detail"),
+            "felt": props.get("felt"),
+            "cdi": props.get("cdi"),
+            "mmi": props.get("mmi"),
+            "alert": props.get("alert"),
+            "status": props.get("status"),
+            "tsunami": props.get("tsunami"),
+            "sig": props.get("sig"),
+            "net": props.get("net"),
+            "code": props.get("code"),
+            "ids": props.get("ids"),
+            "sources": props.get("sources"),
+            "types": props.get("types"),
+            "nst": props.get("nst"),
+            "dmin": props.get("dmin"),
+            "rms": props.get("rms"),
+            "gap": props.get("gap"),
+            "magType": props.get("magType"),
+            "type": props.get("type"),
+            "title": props.get("title"),
+            "longitude": lon,
+            "latitude": lat,
+            "depth": depth,
+        }
+
+        return Event(
+            id=event_id,
+            source="central/adapters/usgs_quake",
+            category=f"quake.event.{tier}",
+            time=event_time,
+            expires=None,
+            severity=severity,
+            geo=geo,
+            data=data,
+        )
+
+    async def poll(self) -> AsyncIterator[Event]:
+        """Poll USGS for earthquake data."""
+        if not self.region:
+            logger.warning("USGS quake region not configured, skipping poll")
+            return
+
+        # Sweep old dedup entries periodically
+        self.sweep_old_ids()
+
+        try:
+            data = await self._fetch_geojson()
+        except Exception as e:
+            logger.error("Failed to fetch USGS data", extra={"error": str(e)})
+            raise
+
+        features = data.get("features", [])
+        metadata = data.get("metadata", {})
+
+        logger.info(
+            "USGS quake poll completed",
+            extra={
+                "feature_count": len(features),
+                "title": metadata.get("title"),
+                "generated": metadata.get("generated"),
+            },
+        )
+
+        new_count = 0
+        for feature in features:
+            event = self._feature_to_event(feature)
+            if event is None:
+                continue
+
+            if self.is_published(event.id):
+                continue
+
+            yield event
+            self.mark_published(event.id)
+            new_count += 1
+
+        logger.info("USGS quake yielded events", extra={"count": new_count})
diff --git a/tests/test_usgs_quake.py b/tests/test_usgs_quake.py
new file mode 100644
index 0000000..6be5f78
--- /dev/null
+++ b/tests/test_usgs_quake.py
@@ -0,0 +1,482 @@
+"""Tests for USGS earthquake adapter."""
+
+import pytest
+from datetime import datetime, timezone
+from unittest.mock import AsyncMock, MagicMock, patch
+from pathlib import Path
+import tempfile
+
+from central.adapters.usgs_quake import (
+    USGSQuakeAdapter,
+    magnitude_tier,
+    magnitude_to_severity,
+)
+from central.config_models import AdapterConfig, RegionConfig
+from central.models import Event, Geo
+
+
+# Sample USGS GeoJSON response
+SAMPLE_GEOJSON = {
+    "type": "FeatureCollection",
+    "metadata": {
+        "generated": 1715878800000,
+        "url": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_hour.geojson",
+        "title": "USGS All Earthquakes, Past Hour",
+        "status": 200,
+        "api": "1.10.3",
+        "count": 3
+    },
+    "features": [
+        {
+            "type": "Feature",
+            "properties": {
+                "mag": 2.5,
+                "place": "10km N of Boise, Idaho",
+                "time": 1715878500000,
+                "updated": 1715878600000,
+                "tz": None,
+                "url": "https://earthquake.usgs.gov/earthquakes/eventpage/us1234",
+                "detail": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/detail/us1234.geojson",
+                "felt": None,
+                "cdi": None,
+                "mmi": None,
+                "alert": None,
+                "status": "automatic",
+                "tsunami": 0,
+                "sig": 100,
+                "net": "us",
+                "code": "1234",
+                "ids": ",us1234,",
+                "sources": ",us,",
+                "types": ",origin,",
+                "nst": 10,
+                "dmin": 0.5,
+                "rms": 0.3,
+                "gap": 100,
+                "magType": "ml",
+                "type": "earthquake",
+                "title": "M 2.5 - 10km N of Boise, Idaho"
+            },
+            "geometry": {
+                "type": "Point",
+                "coordinates": [-116.2, 43.7, 10.5]
+            },
+            "id": "us1234"
+        },
+        {
+            "type": "Feature",
+            "properties": {
+                "mag": 4.5,
+                "place": "20km S of Portland, Oregon",
+                "time": 1715878400000,
+                "updated": 1715878500000,
+                "tz": None,
+                "url": "https://earthquake.usgs.gov/earthquakes/eventpage/us5678",
+                "detail": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/detail/us5678.geojson",
+                "felt": 50,
+                "cdi": 4.0,
+                "mmi": 3.5,
+                "alert": "green",
+                "status": "reviewed",
+                "tsunami": 0,
+                "sig": 300,
+                "net": "us",
+                "code": "5678",
+                "ids": ",us5678,",
+                "sources": ",us,",
+                "types": ",origin,shakemap,",
+                "nst": 25,
+                "dmin": 0.2,
+                "rms": 0.2,
+                "gap": 50,
+                "magType": "mw",
+                "type": "earthquake",
+                "title": "M 4.5 - 20km S of Portland, Oregon"
+            },
+            "geometry": {
+                "type": "Point",
+                "coordinates": [-122.6, 45.3, 15.0]
+            },
+            "id": "us5678"
+        },
+        {
+            "type": "Feature",
+            "properties": {
+                "mag": 3.0,
+                "place": "50km E of San Francisco, California",
+                "time": 1715878300000,
+                "updated": 1715878400000,
+                "tz": None,
+                "url": "https://earthquake.usgs.gov/earthquakes/eventpage/us9999",
+                "detail": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/detail/us9999.geojson",
+                "felt": None,
+                "cdi": None,
+                "mmi": None,
+                "alert": None,
+                "status": "automatic",
+                "tsunami": 0,
+                "sig": 150,
+                "net": "us",
+                "code": "9999",
+                "ids": ",us9999,",
+                "sources": ",us,",
+                "types": ",origin,",
+                "nst": 15,
+                "dmin": 0.3,
+                "rms": 0.25,
+                "gap": 80,
+                "magType": "ml",
+                "type": "earthquake",
+                "title": "M 3.0 - 50km E of San Francisco, California"
+            },
+            "geometry": {
+                "type": "Point",
+                "coordinates": [-121.5, 37.8, 8.0]
+            },
+            "id": "us9999"
+        }
+    ]
+}
+
+# Sample with null magnitude
+SAMPLE_NULL_MAG = {
+    "type": "FeatureCollection",
+    "metadata": {"count": 1},
+    "features": [
+        {
+            "type": "Feature",
+            "properties": {
+                "mag": None,
+                "place": "Quarry blast",
+                "time": 1715878500000,
+                "type": "quarry blast"
+            },
+            "geometry": {
+                "type": "Point",
+                "coordinates": [-116.0, 44.0, 0.0]
+            },
+            "id": "usquarry1"
+        }
+    ]
+}
+
+
+def make_adapter_config(
+    region: dict | None = None,
+    feed: str = "all_hour",
+) -> AdapterConfig:
+    """Create an AdapterConfig for testing."""
+    settings = {"feed": feed}
+    if region:
+        settings["region"] = region
+    else:
+        settings["region"] = {
+            "north": 49.5,
+            "south": 40.0,
+            "east": -110.0,
+            "west": -125.0,
+        }
+
+    return AdapterConfig(
+        name="usgs_quake",
+        enabled=True,
+        cadence_s=60,
+        settings=settings,
+        updated_at=datetime.now(timezone.utc),
+    )
+
+
+@pytest.fixture
+def temp_db_path():
+    """Create a temporary database path for testing."""
+    with tempfile.NamedTemporaryFile(suffix=".db", delete=False) as f:
+        yield Path(f.name)
+
+
+@pytest.fixture
+def mock_config_store():
+    """Create a mock ConfigStore."""
+    return MagicMock()
+
+
+class TestMagnitudeTier:
+    """Test magnitude tier classification."""
+
+    def test_minor(self):
+        assert magnitude_tier(0.5) == "minor"
+        assert magnitude_tier(2.9) == "minor"
+
+    def test_light(self):
+        assert magnitude_tier(3.0) == "light"
+        assert magnitude_tier(3.9) == "light"
+
+    def test_moderate(self):
+        assert magnitude_tier(4.0) == "moderate"
+        assert magnitude_tier(4.9) == "moderate"
+
+    def test_strong(self):
+        assert magnitude_tier(5.0) == "strong"
+        assert magnitude_tier(5.9) == "strong"
+
+    def test_major(self):
+        assert magnitude_tier(6.0) == "major"
+        assert magnitude_tier(6.9) == "major"
+
+    def test_great(self):
+        assert magnitude_tier(7.0) == "great"
+        assert magnitude_tier(9.5) == "great"
+
+
+class TestMagnitudeToSeverity:
+    """Test magnitude to severity mapping."""
+
+    def test_severity_levels(self):
+        assert magnitude_to_severity(2.0) == 0
+        assert magnitude_to_severity(3.5) == 1
+        assert magnitude_to_severity(4.5) == 2
+        assert magnitude_to_severity(5.5) == 3
+        assert magnitude_to_severity(6.5) == 4
+        assert magnitude_to_severity(7.5) == 5
+
+
+class TestRegionFiltering:
+    """Test region/bbox filtering."""
+
+    @pytest.mark.asyncio
+    async def test_filters_out_of_bbox(self, temp_db_path, mock_config_store):
+        """Test that quakes outside bbox are filtered."""
+        # Region covers PNW only (north of 40, west of -110)
+        config = make_adapter_config(
+            region={"north": 49.5, "south": 40.0, "east": -110.0, "west": -125.0}
+        )
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_GEOJSON
+
+            events = []
+            async for event in adapter.poll():
+                events.append(event)
+
+            # us1234 (Boise) and us5678 (Portland) are in bbox
+            # us9999 (SF, lat 37.8) is outside bbox (south < 40)
+            assert len(events) == 2
+            event_ids = {e.id for e in events}
+            assert "us1234" in event_ids
+            assert "us5678" in event_ids
+            assert "us9999" not in event_ids
+
+        await adapter.shutdown()
+
+
+class TestDeduplication:
+    """Test deduplication logic."""
+
+    @pytest.mark.asyncio
+    async def test_dedup_marks_published(self, temp_db_path, mock_config_store):
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        event_id = "us1234"
+
+        assert not adapter.is_published(event_id)
+        adapter.mark_published(event_id)
+        assert adapter.is_published(event_id)
+
+        await adapter.shutdown()
+
+    @pytest.mark.asyncio
+    async def test_second_poll_no_duplicates(self, temp_db_path, mock_config_store):
+        """Test that second poll with same events yields nothing."""
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_GEOJSON
+
+            # First poll
+            events1 = []
+            async for event in adapter.poll():
+                events1.append(event)
+
+            # Second poll - same data
+            events2 = []
+            async for event in adapter.poll():
+                events2.append(event)
+
+            # First poll should have events (2 in bbox)
+            assert len(events1) == 2
+            # Second poll should have 0 (all deduped)
+            assert len(events2) == 0
+
+        await adapter.shutdown()
+
+
+class TestNullMagnitude:
+    """Test handling of null magnitude events."""
+
+    @pytest.mark.asyncio
+    async def test_skips_null_magnitude(self, temp_db_path, mock_config_store):
+        """Test that events with null magnitude are skipped."""
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_NULL_MAG
+
+            events = []
+            async for event in adapter.poll():
+                events.append(event)
+
+            # Should skip the null-magnitude event
+            assert len(events) == 0
+
+        await adapter.shutdown()
+
+
+class TestEventGeneration:
+    """Test Event generation from features."""
+
+    @pytest.mark.asyncio
+    async def test_event_category(self, temp_db_path, mock_config_store):
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_GEOJSON
+
+            events = []
+            async for event in adapter.poll():
+                events.append(event)
+
+            # Check categories
+            categories = {e.category for e in events}
+            # us1234 is M2.5 -> minor, us5678 is M4.5 -> moderate
+            assert "quake.event.minor" in categories
+            assert "quake.event.moderate" in categories
+
+        await adapter.shutdown()
+
+    @pytest.mark.asyncio
+    async def test_event_severity(self, temp_db_path, mock_config_store):
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_GEOJSON
+
+            events = []
+            async for event in adapter.poll():
+                events.append(event)
+
+            # Find events by ID
+            events_by_id = {e.id: e for e in events}
+
+            # M2.5 -> severity 0
+            assert events_by_id["us1234"].severity == 0
+            # M4.5 -> severity 2
+            assert events_by_id["us5678"].severity == 2
+
+        await adapter.shutdown()
+
+    @pytest.mark.asyncio
+    async def test_event_geo(self, temp_db_path, mock_config_store):
+        config = make_adapter_config()
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        with patch.object(adapter, "_fetch_geojson", new_callable=AsyncMock) as mock_fetch:
+            mock_fetch.return_value = SAMPLE_GEOJSON
+
+            events = []
+            async for event in adapter.poll():
+                events.append(event)
+
+            events_by_id = {e.id: e for e in events}
+
+            # Check Boise quake coordinates
+            boise = events_by_id["us1234"]
+            assert boise.geo.centroid == (-116.2, 43.7)
+
+        await adapter.shutdown()
+
+
+class TestApplyConfig:
+    """Test hot-reload configuration application."""
+
+    @pytest.mark.asyncio
+    async def test_apply_config_updates_region(self, temp_db_path, mock_config_store):
+        config = make_adapter_config(
+            region={"north": 49.5, "south": 40.0, "east": -110.0, "west": -125.0}
+        )
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        assert adapter.region.north == 49.5
+
+        new_config = make_adapter_config(
+            region={"north": 48.0, "south": 45.0, "east": -115.0, "west": -125.0}
+        )
+        await adapter.apply_config(new_config)
+
+        assert adapter.region.north == 48.0
+        assert adapter.region.south == 45.0
+
+        await adapter.shutdown()
+
+    @pytest.mark.asyncio
+    async def test_apply_config_updates_feed(self, temp_db_path, mock_config_store):
+        config = make_adapter_config(feed="all_hour")
+        adapter = USGSQuakeAdapter(
+            config=config,
+            config_store=mock_config_store,
+            cursor_db_path=temp_db_path,
+        )
+        await adapter.startup()
+
+        assert adapter._feed == "all_hour"
+
+        new_config = make_adapter_config(feed="all_day")
+        await adapter.apply_config(new_config)
+
+        assert adapter._feed == "all_day"
+
+        await adapter.shutdown()