Logo link to homepage

Report on Ruby (United States) — 4 October-10 October 2023


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 4 October-10 October 2023
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2023. Report on Ruby (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 4 October-10 October 2023. Smithsonian Institution and US Geological Survey.

Weekly Report (4 October-10 October 2023)


United States

15.605°N, 145.572°E; summit elev. 174 m

All times are local (unless otherwise noted)

The US Geological Survey lowered both the Aviation Color Code and Volcano Alert Level for Ruby to Unassigned on 6 October, noting that eruptive activity was last detected during 14-15 September. The level of Unassigned reflected the lack of nearby monitoring instruments that could detect lower-level events.

Geological Summary. Ruby is a basaltic submarine volcano that rises to within about 200 m of the ocean surface near the southern end of the Mariana arc NW of Saipan. An eruption was detected in 1966 by sonar signals (Norris and Johnson, 1969). Submarine explosions were heard in 1995, accompanied by a fish kill, sulfurous odors, bubbling water, and the detection of volcanic tremor.

Source: US Geological Survey