seismology-data-guide

Seismology Data Guide

A skill for processing seismic data, analyzing earthquake catalogs, and working with seismograms using standard tools in observational seismology. Covers data retrieval from global networks, waveform processing with ObsPy, magnitude estimation, focal mechanism analysis, and seismic hazard assessment.

Seismic Data Sources

Global Data Centers

Retrieving Earthquake Catalogs

from obspy.clients.fdsn import Client
from obspy import UTCDateTime

client = Client("IRIS")

# Fetch earthquake catalog for a region and time window
catalog = client.get_events(
    starttime=UTCDateTime("2024-01-01"),
    endtime=UTCDateTime("2024-12-31"),
    minmagnitude=5.0,
    maxmagnitude=9.0,
    minlatitude=30.0, maxlatitude=45.0,
    minlongitude=125.0, maxlongitude=150.0,
    orderby="magnitude",
)

print(f"Found {len(catalog)} events")
for event in catalog[:5]:
    origin = event.preferred_origin()
    mag = event.preferred_magnitude()
    print(f"  M{mag.mag:.1f} {origin.time} "
          f"({origin.latitude:.2f}, {origin.longitude:.2f}) "
          f"depth={origin.depth/1000:.1f} km")

Waveform Processing

Retrieving and Preprocessing Seismograms

from obspy import UTCDateTime
from obspy.clients.fdsn import Client

client = Client("IRIS")

# Download waveform data for a specific event
t = UTCDateTime("2024-01-01T07:10:00")
st = client.get_waveforms(
    network="IU", station="ANMO", location="00", channel="BHZ",
    starttime=t, endtime=t + 600,  # 10 minutes of data
)

# Standard preprocessing pipeline
st.detrend("demean")        # Remove mean
st.detrend("linear")        # Remove linear trend
st.taper(max_percentage=0.05, type="cosine")  # Taper edges
st.filter("bandpass", freqmin=0.01, freqmax=5.0, corners=4)

# Remove instrument response to get ground velocity (m/s)
inv = client.get_stations(
    network="IU", station="ANMO", location="00", channel="BHZ",
    starttime=t, endtime=t + 600, level="response",
)
st.remove_response(inventory=inv, output="VEL", pre_filt=[0.005, 0.01, 8, 10])