Update, September 18, 2021, 9:15 a.m., Pacific: Per INVOLCAN’S Facebook page — the only constantly updated online official resource I can find — seismicity and ground deformation are ongoing, but no thermal anomalies have been detected yet.
Again, the most likely scenario here, IMO, if the magma intrusion doesn’t stall out, is an eruption, perhaps as spectacular as the one in 1971.
Gigantic landslide risk is very, very small, per the Global Volcanism Program.
There is an intense seismic swarm (Spanish) ongoing here, and they just raised the alert level to Yellow this afternoon.
There’s special excitement on the Internet about this because of featured news back in the 00’s about a megatsunami hitting the US East Coast — particularly Florida — after potential flank collapse at this volcano.
Actually the whole island of La Palma is the edifice, with the southern volcanic center of Cumbre Vieja currently the most active. Here is the Smithsonian GVP page.
This volcano erupts frequently, last in the 1970s, and there has been no collapse. If it erupts now, there will probably be no collapse.
Even if there is, as I understand this, it most likely would be small and occur in a stepwise manner, per the sources I checked for writing about the nearby Decade Volcano Teide, on Tenerife, not as a big splash.
Such things do happen in the Canaries, at Mauna Loa and Kilauea, and elsewhere on land and island volcanoes. Only they happen at very long intervals. And it can happen without warning, too.
There’s just a lot of public concern about this one volcano now, I suspect because of that BBC special 21 years ago.
The volcanologists are on it, as always. This restlessness will be closely followed internationally, I’m sure. Hopefully, after scaring everyone, Cumbre Vieja will roll over and doze off again. If not that, then the eruption will probably be something along the lines of 1971, though perhaps at a different vent.
For anyone interested in the technical details of tsunami risk at Cumbre Vieja, here’s one of the papers I found via Google Scholar.
This is also my post at Talkweather.
Featured image: KrisNM, CC BY-NC-ND 2.0