FDSN quickstart — recent earthquakes¶

Fetch recent global M5+ earthquakes from the USGS ComCat catalog through the earthlens FDSN backend, and plot them. FDSN is the first vector backend: download() returns a pyramids FeatureCollection (a geopandas.GeoDataFrame), not a raster.

Install with pip install earthlens[fdsn] (pulls in obspy).

Setup¶

Import EarthLens and create the output directory. The FDSN backend writes the query result to a GeoPackage on disk and also returns it in memory.

In [ ]:

from pathlib import Path

from earthlens import EarthLens

OUT_DIR = Path('fdsn_output')
OUT_DIR.mkdir(exist_ok=True)

from pathlib import Path from earthlens import EarthLens OUT_DIR = Path('fdsn_output') OUT_DIR.mkdir(exist_ok=True)

Build the query¶

variables=['USGS'] selects the network; query filters (min_magnitude, …) are explicit keyword arguments. Building the request is its own step, kept separate from the network call below.

In [ ]:

fdsn = EarthLens(
    variables=['USGS'],
    data_source='fdsn',
    start='2024-01-01',
    end='2024-01-31',
    aoi=[-180, -90, 180, 90],
    min_magnitude=5.0,
    path=str(OUT_DIR),
)

fdsn = EarthLens( variables=['USGS'], data_source='fdsn', start='2024-01-01', end='2024-01-31', aoi=[-180, -90, 180, 90], min_magnitude=5.0, path=str(OUT_DIR), )

Download the events¶

download() runs the live USGS query, writes fdsn_output/usgs.gpkg, and returns the events in memory. The call is wrapped so the notebook stays safe under nbval-lax when run offline (the cell never raises).

In [ ]:

events = None
try:
    events = fdsn.download()
    print(f'{len(events)} events')
except Exception as exc:
    print(f'live FDSN query skipped (offline?): {type(exc).__name__}: {exc}')

events = None try: events = fdsn.download() print(f'{len(events)} events') except Exception as exc: print(f'live FDSN query skipped (offline?): {type(exc).__name__}: {exc}')

Inspect the events¶

In [ ]:

if events is not None and len(events):
    display(events[['time', 'magnitude', 'depth_km', 'provider', 'geometry']].head())
    print('CRS:', events.crs)

if events is not None and len(events): display(events[['time', 'magnitude', 'depth_km', 'provider', 'geometry']].head()) print('CRS:', events.crs)

Plot the epicentres¶

Marker area scales with magnitude.

In [ ]:

if events is not None and len(events):
    ax = events.plot(markersize=events['magnitude'] ** 2, alpha=0.5, color='firebrick')
    ax.set_title('M5.0+ earthquakes, January 2024 (USGS)')
    ax.set_xlabel('longitude')
    ax.set_ylabel('latitude')

if events is not None and len(events): ax = events.plot(markersize=events['magnitude'] ** 2, alpha=0.5, color='firebrick') ax.set_title('M5.0+ earthquakes, January 2024 (USGS)') ax.set_xlabel('longitude') ax.set_ylabel('latitude')