Earthquakes near West Covina through history

The deadliest was not the strongest: a magnitude 6.4 on March 11, 1933 (The 1933 Long Beach, California Earthquake), for which NOAA records 120 deaths. NOAA’s list of significant earthquakes has 26 here, back to 1812. NOAA records deaths in 14 of the events here, 313 in all. The latest on NOAA’s list is a magnitude 7.1 on July 6, 2019 (Ridgecrest Earthquake Sequence). NOAA’s record here begins on December 8, 1812 with an earthquake (San Juan Capistrano). It grows thinner going back: 20 of the 26 significant earthquakes NOAA lists here are from 1927 on. NOAA lists 6 tsunamis that began within 100 km of West Covina, and 8 from elsewhere that reached it with deaths or a metre of water or more. The highest water NOAA records here was 3.05 m, on August 31, 1930. The deadliest, on August 31, 1930, killed one person here by NOAA’s runup records.

• July 6, 2019Earthquake · M 7.1Ridgecrest Earthquake SequenceUSGS · NOAA NCEI
• July 21, 1952Earthquake · M 7.5The 1952 Kern County, California Earthquake · 12 deaths (NOAA)USGS · NOAA NCEI · Wikipedia
• March 11, 1933Earthquake · M 6.4The 1933 Long Beach, California Earthquake · 120 deaths (NOAA)USGS · NOAA NCEI · Wikipedia
• August 31, 1930Tsunami · 3.05 m hereS. California · one death here (NOAA)NOAA NCEI
• December 21, 1812Earthquake · M 7.5 (est.)Purisima · one death (NOAA)NOAA NCEI · Wikipedia
• December 8, 1812Earthquake · M 6.9 (est.)San Juan Capistrano · 40 deaths (NOAA)NOAA NCEI · Wikipedia

• An event counts for West Covina when it began within 100 km of its centre, or 200 km for an earthquake of magnitude 7 or more. Damage can reach further.
• USGS counts here start at magnitude 6: the catalogue’s smaller quakes thin out going back, where few instruments listened.
• NOAA lists significant events only: earthquakes that killed, did about $1 million of damage, reached magnitude 7.5 or intensity X, or raised a tsunami, and eruptions and tsunamis by like measures. Magnitudes before 1900 are its estimates from written accounts.
• Deaths are NOAA’s total for each event, wherever people died, its tsunami and fires included. A tsunami counts the dead its runup records give for this place: NOAA’s total for a tsunami includes its source quake’s.
• A tsunami from elsewhere counts where one of its runups killed or rose a metre or more.
• Counted to October 19, 2026, as is the map. The last 30 days ask USGS again.

How the layers work, where their data comes from and what they can’t tell you: Earthquakes, live, The world through history