Volcanic

Discolored water with increased likelihood of submarine volcanic activity is reported in Northern Mariana Islands vicinity at 20-26N 145-01E on July 16 at 0013Z.

North Pacific Ocean · HYDROPAC 2039/26

What this record establishes

Listed in force

The latest collected record lists this warning as active. This is the status of the notice, not a live observation of conditions at the location.

Source and dates
NGA MSI in-force warnings (DailyMem*.txt). Issued 2026-07-16 18:11Z. First collected 2026-08-17 13:41Z; last seen in collection 2026-10-01 11:02Z. Collection dates record ingestion, not a new incident or a fresh field observation.
Location covered
North Pacific Ocean. The parsed report position is 20.433, 145.017. It is a position in the source message, not a live location. Check the original wording for limits and qualifications.

Related notices and cancellation links

These reports were linked by category and sea, with positions within 30 nautical miles and issue dates within 30 days of another report's recorded in-force span. Links can extend through other members, so the full group can cover a larger area or period. Proximity does not confirm that they describe one incident.

  1. HYDROPAC 12/242024-01-01 · Cancelled notice
  2. HYDROPAC 153/242024-01-13 · Cancelled notice
  3. NAVAREA XI 322/262026-07-16 · Listed in force
  4. HYDROPAC 2039/26 · this notice2026-07-16 · Listed in force
Compare all 4 notices, changes and original texts →

Current notices and reporting history in the North Pacific Ocean →

issued
2026-07-16 18:11Z
status
Listed in force
sea
North Pacific Ocean
position
20.433, 145.017
nearest port
Saipan · 315 nm
source
NGA MSI in-force warnings (DailyMem*.txt) · first seen 2026-08-17 13:41Z

Original warning text

NORTH PACIFIC.
NORTHERN MARIANA ISLANDS.
1. DISCOLORED WATER WITH INCREASED LIKELIHOOD
   OF SUBMARINE VOLCANIC ACTIVITY REPORTED
   IN VICINITY 20-26.00N 145-01.00E AT 160013Z JUL.
2. CANCEL HYDROPAC 153/24.

Reading this warning

Discoloured water
Patches of unusually coloured sea — often a sign of a submarine volcano or of a shoal.
Volcanic activity
An erupting or restless volcano near or under the sea, with a keep-clear radius around it.
Position (degrees and minutes)
How warnings write positions: degrees, a hyphen, then minutes, with N/S and E/W — 49-40.8N 003-43.8W.
Date-time group (DTG)
A compact UTC timestamp — day, hour and minute followed by Z — such as 201500Z for the 20th at 15:00 UTC.
Cancellation reference
A line that cancels an earlier warning by its number, such as CANCEL HYDROLANT 1085/12.
HYDROPAC
The U.S. long-range warning series for the Pacific outside NAVAREA XII and for the Indian Ocean, Persian Gulf and adjoining seas.

All warning terms →

Nearest volcano

Ahyi · 1 km

Smithsonian GVP record · weekly activity report · Wikidata

Conditions at the position · now

loading…

MET Norway · NOAA WaveWatch III · HYCOM · GEBCO 2020 · model data at the centroid, not an observation

Collected reports in this area · volcanic activity

10 within 180 nm since 1999 · 2 in the last 12 months · 2 listed in force now

99
00
05
10
15
20
25
26

Counts include repeat notices about the same situation. NGA archive coverage ends 2024-05; live collection began 2026-08-17. The period between them is incomplete. An empty year is not evidence that no hazards occurred.

Month of issue in the collected archive

J
F
M
A
M
J
J
A
S
O
N
D

All available years combined. Uneven collection and repeat bulletins affect these counts; this chart does not measure the seasonality or probability of incidents.

Nearby notices listed in force · within 120 nm

Worldwide in the collected sources

12 volcanic activity listed in force · see all

Record snapshot 2026-10-01 11:02Z; source collection times vary.

Volcanic

Submarine eruptions, discoloured water, pumice rafts. All current volcanic activity →

Not for navigation. This is a re-rendering of an official navigational warning for awareness; mariners must use official NAVAREA broadcasts and their national MSI service.