M 7.4 - 2025 Drake Passage Earthquake - unusual

[Astronuc]

M 7.4 - 2025 Drake Passage Earthquake​

• 2025-05-02 12:58:26 (UTC)
• 56.782°S 68.209°W
• 10.0 km depth

https://earthquake.usgs.gov/earthquakes/eventpage/us7000pwkn/executive

The May 2, 2025 magnitude 7.4 earthquake off the southern coast of Chile and Argentina occurred as the result of reverse faulting at shallow depth. The earthquake occurred on either a northeast or southwest dipping reverse fault beneath the Drake Passage, consistent with relative plate convergence motions in the region. The May 2 earthquake occurred in a region of complex tectonic interactions. Here, the South America, Antarctic, and Scotia plates meet at a single point, termed a triple junction. The Antarctic and South America plates form a predominantly convergent boundary, with Antarctica converging eastward at approximately 16 mm/yr relative to the South America plate. The Antarctica-Scotia plate boundary is predominantly a convergent boundary in the north, as evidenced by focal mechanism solutions in the region, and transitions to an oblique-convergent boundary further to the south. The South America-Scotia plate boundary trends east-west across the southern tip of the South American continent, forming a transform plate boundary.


While commonly plotted as points on maps, earthquakes of this magnitude are more appropriately described as slip over a larger fault area. Thrust faulting events of the size of the May 2, 2025, event are typically about 60 km by 35 km (length x width).

Since 1900, 12 other earthquakes of magnitude 6 or larger have occurred within 350 km of this earthquake, including three magnitude 7 and larger earthquakes. Magnitude 7.7 and 7.6 earthquakes occurred on the same day in 1949 along the east-west trending boundary between the Scotia and South America plates in southern Argentina. Additionally, a magnitude ~7.1 earthquake occurred in 1910 south of the May 2, 2025 earthquake along the boundary between the Antarctic and Scotia plates.

The M7.4 earthquake affected populated areas (towns) in the southern tip of Chile and Argentina.

I was wondering if there is any connection with, even thought the two are far apart.

M 6.0 - southern East Pacific Rise​

• 2025-05-05 03:55:40 (UTC)
• 35.275°S 107.429°W
• 10.0 km depth

https://earthquake.usgs.gov/earthquakes/eventpage/us7000px6v/executive

 

[jedishrfu]

Any more details on the unusualness of this quake?

 

[SeaUnRisible]

M 7.4 - 2025 Drake Passage Earthquake​

• 2025-05-02 12:58:26 (UTC)
• 56.782°S 68.209°W
• 10.0 km depth

https://earthquake.usgs.gov/earthquakes/eventpage/us7000pwkn/executive


The M7.4 earthquake affected populated areas (towns) in the southern tip of Chile and Argentina.

I was wondering if there is any connection with, even thought the two are far apart.

M 6.0 - southern East Pacific Rise​

• 2025-05-05 03:55:40 (UTC)
• 35.275°S 107.429°W
• 10.0 km depth

https://earthquake.usgs.gov/earthquakes/eventpage/us7000px6v/executive

How might this intersection be affected by Antarctic glacial melt/failure? Could tectonic energies interplay with glacial failure dynamics in this (or other) junctures?

 

[Baluncore]

I was wondering if there is any connection with, even thought the two are far apart.

How might this intersection be affected by Antarctic glacial melt/failure? Could tectonic energies interplay with glacial failure dynamics in this (or other) junctures?

M 7.4 - 2025 Drake Passage.
2025-05-02 12:58:26 (UTC) 56.782°S 68.209°W 10.0 km depth
M 6.0 - southern East Pacific Rise.
2025-05-05 03:55:40 (UTC) 35.275°S 107.429°W 10.0 km depth

It is very unlikely that the two events are synchronised, as they are far apart in space and time. They are also in quite different tectonic plate environments. The only similarity is the 10 km depth in the crust.

The trigger for the first quake, would be due to the sum of all stresses in the local crust at that time. Those effects, and the occurrence of the first event, would have been attenuated within a few hours, so could not be a direct trigger for the second event, almost 3 days later.

The diurnal, rise and fall of the sea tides, due to the Moon and Sun, is much greater than the solid Earth tide, which again is greater than the rise in sea level due to global ice melt and global warming. A local floating iceberg will have little effect on the tectonic loads, as it neatly displaces its weight of water.

Only the melting of glaciers resting on land, above sea level, in the Southern Andes near the Beagle Channel, might have some effect on the unloading or rebound of the crust. But the earthquakes were not there.

The three-day delay between the two events, is much too long to be due to tidal propagation in longitude, due to rotation of the Earth. It is also too long to be due to seismic velocity in the Earth's crust.

The two events should be treated as being quite independent. If you want to argue differently, you would need to establish some mechanism and relationship, in time and space, that might correlate the two distant events.