Earthquakes near Pátra through history

The deadliest was not the strongest: an estimated magnitude 7.1 on July 7, 551 (Schisma, Boetia), for which NOAA records 5,000 deaths. NOAA’s list of significant earthquakes has 61 here, back to 427 BCE. NOAA records deaths in 28 of the events here, 9,775 in all. The latest on NOAA’s list is a magnitude 5.3 on August 7, 2013 (Central: Phthiotis, Reggini). NOAA’s record here begins in 427 BCE with an earthquake (Euboea). It grows thinner going back: 22 of the 61 significant earthquakes NOAA lists here are from 1927 on. NOAA lists 31 tsunamis that began within 100 km of Pátra, and 2 from elsewhere that reached it with deaths or a metre of water or more. The highest water NOAA records here was 12 m, on August 23, 1817. The deadliest, on August 23, 1817, killed 18 people here by NOAA’s runup records.

• August 7, 2013Earthquake · M 5.3Central: Phthiotis, RegginiNOAA NCEI
• October 6, 1947Earthquake · M 7.34 km WNW of Koróni, Greece · 3 deaths (NOAA)USGS · NOAA NCEI
• September 30, 1870Earthquake · M 7.5 (est.)100 deaths (NOAA)NOAA NCEI
• August 23, 1817Tsunami · 12 m hereCorinthos-Patras Gulf · 18 deaths here (NOAA)NOAA NCEI
• July 7, 551Earthquake · M 7.1 (est.)Schisma, Boetia · 5,000 deaths (NOAA)NOAA NCEI
• 427 BCEEarthquake · M 7.1 (est.)Euboea · 2,500 deaths (NOAA)NOAA NCEI

• An event counts for Pátra 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