In a recent news article (published on 6 May 2019), Stephen Johnson reports that we may be seeing evidence of the birth of a subduction zone (for the non-geologists a subduction zone is where one tectonic plate is being driven under another).
Since 1969, some geologists have been puzzled by a 7.9-magnitude earthquake that occurred beneath a flat, featureless region off the coast of Portugal that’s since been the location of several earthquakes. Now, a team believe that a drip-shaped mass, buried 155 miles (250 km) below the seafloor, might be responsible for the seismic activity and that the drip-shaped anomaly may represent the early stages of a new subduction zone. You can find the entire article here: https://bigthink.com/surprising-science/subduction-zone-portugal
