There is no world authority on whether a volcano is erupting. There are about thirty national observatories, each with its own alert scale, its own vocabulary, its own update schedule, and in several cases its own language. Nobody harmonised them, and the attempts to translate between them produce nonsense.
This matters more than it sounds, because the single most common way travellers get bad information is by reading a number from one country's system through the assumptions of another's.
Level 3 means four different things
Take the number three, which several countries happen to use.
In New Zealand, volcanic alert level 3 means a minor eruption is already in progress. In the Philippines, alert level 3 means magmatic unrest with an eruption considered possible, and nothing is erupting. In Indonesia, level 3 (Siaga) means an eruption is underway that does not yet threaten settlements. In Iceland, level 3 is the top of the scale.
So a traveller who learns what level 3 means in one country and carries that understanding to another will be wrong, and depending on the direction of the mistake, wrong in the dangerous direction.
| Country or agency | Scale | Starts at | Quirk worth knowing |
|---|---|---|---|
| United States (USGS) | Four named levels | NORMAL | Words rather than numbers: Normal, Advisory, Watch, Warning |
| Indonesia (PVMBG) | Four levels, I to IV | Level I | There is no level zero. Normalising it to a 0-based scale shifts everything by one |
| Philippines (PHIVOLCS) | Six levels, 0 to 5 | 0 | The scale is defined separately for each volcano, and the same level carries different names on different mountains |
| New Zealand (GeoNet) | Six levels, 0 to 5 | 0 | Eruption in progress covers levels 3, 4 and 5, so the scale describes size once it starts |
| Iceland (IMO) | Four levels, 0 to 3 | 0 | Level 3 is the maximum, not a mid-point |
| Italy (INGV) | None | not applicable | The observatory publishes measurements. The alert colour is set by the civil protection department, which is a different body |
That last row surprises people. There is no such thing as an INGV alert level for Etna. The institute monitors and publishes bulletins; the green, yellow, orange and red you may have seen belong to the national civil protection system, and access decisions are made by mayors acting on it. If a website tells you the current INGV alert level, it has invented a category.
The aviation colour code is not the alert level
This one catches out even careful readers, and it is the mistake most likely to appear in an otherwise well-written travel article.
Volcanoes carry a second, entirely separate indicator: a four-colour aviation code, from green to red, which exists to tell pilots and air traffic control about ash in the atmosphere. It answers a question about aircraft engines. It says nothing about whether the ground is safe or the trail is open.
The two can point in opposite directions on the same volcano on the same day. A volcano can be red for aviation while the ground hazard is unremarkable, because a modest ash plume matters enormously to a jet and very little to a person standing several kilometres away. It can equally be green for aviation while the ground is closed, because gas and unstable terrain do not produce ash clouds.
The aviation colour code is independent of the Volcano Alert Level System, and these two colour codes may differ at any given time.
Iceland also has a fifth aviation colour that most systems lack: grey, meaning the volcano appears quiet but is not adequately monitored. It is an honest category and I wish more agencies had one.
The lesson buried in every scale
Alert level zero does not mean nothing can hurt you
Every scale has a bottom rung, and travellers read it as safe. The agencies themselves are careful not to.
New Zealand's guidance states plainly that at the lowest level, volcanic environment hazards remain: hydrothermal activity, earthquakes, landslides, gas, lahars. Italy's Etna bulletins go further and note that certain phenomena can occur without any precursor at all, which means the level of hazard is never zero.
This is not agencies covering themselves. It is the accurate description of a landscape where hot water sits under thin ground, where gas pools in hollows on still days, and where a slope of loose ash becomes a mudflow in heavy rain. None of those need an eruption.
The practical version: the alert level tells you what the volcano is doing, not whether the place is safe. Those are different questions and the second one is mostly answered by the trail, the weather and the guide.
Who to check, by destination
Go to the monitoring agency, not to a travel site. Travel sites, including official tourism ones, have been observed carrying eruption status text left unchanged for the better part of a year.
| Destination | Agency | What it publishes |
|---|---|---|
| Hawai'i | USGS Hawaiian Volcano Observatory | Daily updates, alert level, aviation code, live webcams |
| Mount Rainier, Mount St. Helens | USGS Cascades Volcano Observatory | Status updates and notifications |
| Etna, Stromboli, Vulcano | INGV Osservatorio Etneo | Weekly multidisciplinary bulletins and event communiqués, plus streaming cameras |
| Vesuvius, Campi Flegrei | INGV Osservatorio Vesuviano | Monthly bulletins |
| Iceland | Icelandic Meteorological Office | Hazard assessment maps with an explicit valid-until date, plus aviation codes |
| Bali, Java, Lombok | PVMBG, via the MAGMA Indonesia service | Daily reports for 69 volcanoes, alert level, and sector-by-sector exclusion distances |
| Japan | Japan Meteorological Agency | Five-level warnings, distinguishing near-crater from residential-area warnings |
| New Zealand | GeoNet | Volcanic alert bulletins, with the full history published openly |
| Guatemala | INSIVUMEH | Daily and special bulletins for Fuego, Pacaya and Santiaguito, plus webcams |
| Costa Rica | OVSICORI at Universidad Nacional | Daily reports for Poás, Turrialba, Arenal and Rincón de la Vieja |
| Ecuador | Instituto Geofísico, Escuela Politécnica Nacional | Daily reports for Cotopaxi, Sangay and Reventador |
| Philippines | PHIVOLCS | Per-volcano alert levels and permanent danger zones |
| Canary Islands | Instituto Geográfico Nacional and INVOLCAN | Seismic and deformation monitoring |
How to read a bulletin without being a volcanologist
Four things, in this order.
The date and time on the reading itself. Not on the page, on the number. The best agencies stamp each measurement individually: a sulphur dioxide flux figure carries the date it was measured, a crater lake temperature carries the date it was taken. If a page shows a status but no measurement date, you cannot tell whether it is from this morning or from 2015. This happens more often than you would like.
The exclusion distance, and whether it is a radius. Indonesian bulletins are the most useful in the world on this point, because they publish distances in kilometres and they publish them by sector. Merapi's exclusions differ depending on which valley you are in. Semeru's extend far down one particular river channel because that is where the mudflows go. A single radius is a simplification and often the wrong one.
Whether visitors are mentioned at all. Indonesia's service is unusual in naming tourists, climbers and visitors explicitly in its recommendations. Most agencies write for civil protection officials, which means the guidance you are reading was not written with you in mind.
What the agency says can happen without warning. This is the sentence buried near the bottom, and it is the most useful one on the page.
A word about the sources you will find first
Search for volcano status and you will mostly get aggregators. Some are careful. Many carry text that has not been touched in months, and a few contradict themselves on the same page because one section is automated and another was written by hand.
We have watched an official-looking safety page carry an eruption status from the previous autumn for eleven months, while the air quality monitor a few kilometres away was reading badly. We have seen an alert status published with a date stamp eleven years old.
Which is why this page contains no volcano statuses. Anything we published here would be wrong within weeks, and being wrong slowly is worse than not answering, because nothing on the page would tell you it had gone stale. The agencies above are one click away and they are the ones who actually know.
Quick answers
Is there one website that shows every erupting volcano?
The closest thing is the joint Smithsonian and USGS weekly activity report, which summarises new and continuing activity worldwide and is published every Thursday. It is a summary of what the national agencies reported, so for anything you plan to act on, go to the agency itself.
The alert level went up while I am on holiday. Is my tour cancelled?
Usually the operator will know before you do, because in most jurisdictions the obligation falls on licensed guides to suspend activity immediately when the level changes, without waiting for a new ordinance. If you have not heard from them, contact them rather than assuming.
What does it mean when a volcano is red for aviation but tours are running?
It usually means there is ash in the atmosphere at altitudes that concern aircraft, while ground hazard in the visitor area is being separately assessed as acceptable. The two systems answer different questions. Follow the ground authority for whether to walk, and expect flight disruption regardless.
How much warning is there before an eruption?
It depends entirely on the volcano and the type of event. Some systems give days or weeks of measurable unrest. Some give tens of minutes, as in the Icelandic dyke intrusions. And some events, including gas releases and steam-driven explosions, have no useful precursor at all, which is exactly why observatories say hazard is never zero.
Destinations where activity is not the variable
For most volcano trips the eruption is a bonus rather than the plan. These are the places where the landscape carries the visit on its own.
Data verified on. Alert scale definitions come from each agency's own published documentation. We deliberately publish no volcano statuses here: those belong on the observatory pages linked above. Editorial Policy