[3] Scientists were alerted to the presence of the tear by the depth of strike-slip earthquakes, which were occurring too deep for them to be in the overriding plate.
The Sirena Deep lies at the intersection of the East Santa Rosa Bank Fault and a trench axis south of Guam.
The new name references the Guam folk-tale of Sirena, a young girl turned into half fish because of her disobedience.
On 7 May 2019 Victor Vescovo (Pilot) and Alan Jamieson (Chief Scientist) made the first crewed descent to the bottom of the Sirena Deep in the Deep-Submergence Vehicle Limiting Factor (a Triton 36000/2 model submersible) and measured a depth of 10,714 m (35,151 ft) ±10 m (33 ft) by direct CTD pressure measurements.
They spent 176 minutes on the bottom of the Sirena Deep and the deepest piece of mantle rock ever recovered from the surface of the western slope of the Mariana Trench was collected.