Ruby Seamount
From Wikipedia, the free encyclopedia
| Ruby Seamount | |
|---|---|
 Major volcanoes of the Mariana Islands | |
 Ruby Seamount bathymetry | |
| Summit depth | 175 m (574 ft)[1] |
| Location | |
| Location | Pacific Ocean |
| Group | Izu–Bonin–Mariana Arc |
| Coordinates | 15°37′12″N 145°34′12″E / 15.62000°N 145.57000°E[2] |
| Country | Commonwealth of Northern Mariana Islands, United States |
| Geology | |
| Type | Seamount |
| Age of rock | |
| Last eruption | 15 September 2023 |
Ruby Seamount is an active volcanic seamount in the Northern Mariana Islands region of the Pacific Ocean about 50 km (31 mi) north-west of Saipan.[5][2] It is in a region where the Pacific Plate is subducting under the Philippine Sea Plate producing arc volcanism.
Geology
Ruby Seamount is a stratovolcano with a more shallow southern peak,[5] and is part of the nine volcano Southern Seamount Province of the Mariana Arc, in the Izu–Bonin–Mariana Arc.[3]: 151 Its location is consistent with it being a back-arc extension associated volcano. Samples of lava have been characterised as arc tholeiitic basalts,[3] suggestive that the magma source was from mantle overlying, not beneath, the subducting Pacific Plate.[4]: 15092–3 The age of the volcano is unknown but nearby basalts have been dated at about 2 million years old,[4]: 15094–6 so it likely started forming more recently than this.
Hydrothermal activity was demonstrated in 2006 with alkaline, ferrous ion and carbon dioxide venting at 200 m (660 ft) depth.[1]: 7, 11 The ratio of CO2 / 3He flux observed at Ruby is amongst the highest ever reported, which is consistent with volcanism involving a deep magma source from slab derived carbonate containing rocks.[1]: 18
Depth revision
Prior to the 1995 eruption the depth was accepted as 230 m (750 ft),[2] but several reports of shallower depths followed the eruption including one of only about 60 m (200 ft) exist.[5] A high quality survey in 2003 gave a depth of 180 m (590 ft) with the peak of North Ruby having a depth of 726 m (2,382 ft).[6]: 16 The next high quality survey in 2006 gave a new depth of 175 m (574 ft).[1]: 11