Europe, Iceland, Portugal

São Jorge Earthquake Swarm, Update 07.04.2022

Good morning!

The earthquake swarm is continuing on São Jorge as we write, albeit it at a much lower intensity.  The swarm is located on the Manadas Fissure system.  INVOLCAN has sent a team to assist the local scientists (CIVISA and IVAR).   CIVISA advised on 6 April 2022 that volcano-tectonic earthquakes had been detected suggesting magma movement at depth.

Fig 1: Image of Fajã dos Cubres, São Jorge, Azores, cropped from one by Jules Verne Times Two.  Published under CC BY-SA 4.0 (Source: São Jorge Island – Wikipedia).

While we wait to see what transpires, here are some statistics.

  • Number of earthquakes ≥2.0 reported on IPMA’s site: 793
  • Maximum number: 127 on 20 March 2022
  • Minimum number: 5 on 31/03/2022 and 06/04/2022 (7/04/2022 is not a complete day)
  • Maximum magnitude: 4.0 (29/03/2022, 21:56:16, 38.686°N, 28.215°W, 10km)
  • Maximum depth: 26km on 20 March 2022 and 28km on 28 March 2022.
Fig 2: Number of earthquakes by day by the author.  © remains with the author; all rights reserved, 2022.
Fig 3: Earthquake depth and magnitude by day by the author. © copyright remains with the author; all rights reserved, 2022.

We have updated our earthquake plots for 38.548°N, 27.677°W to 38.769°N, 28.350°W from 19th March 2022 to 7th April 2022.

Fig 4: Video of geoscatter and scatter plots of the earthquake swarm from 19th March 2022 to 7th April 2022.  Keys are in the video. © copyright remains with the author; all rights reserved, 2022.

Armchair Volcanologist

© copyright remains with the author; all rights reserved, 2022.

Sources

 IPMA – Seismic Map (for raw earthquake data)

Volcano-tectonic tremors recorded for first time on quake-hit Azores island | Reuters