A 3D model of Vesuvius, Monte Somma and the plain to the east, made from satellite images and elevation data. As the story plays, lava flows spread north towards San Sebastiano and south-east, lava fountains rise from the crater, and an ash column drifts east and then south-west. The panel describes each moment in words.
Vesuvius, March 1944
Photos and eyewitnesses archive
How this works
Where the lava goes comes from the same method as the Vesuvius lava page (DOWNFLOW, Favalli and colleagues 2005), run on today's ground for the two 1944 flows: north (stopping at about 140 m above sea level) and south-east (about 350 m). Lava is drawn where at least 1 in 5 of the simulated flows went.
When it gets there is an estimate. The lava moves at a steady speed, set so that the northern flow reaches San Sebastiano early on 21 March, as recorded. The real speed varied from 50 to 300 m an hour. The colors show lava cooling from yellow-hot to a dark crust, and are for illustration.
The eruption column follows INGV's account: lava fountains throwing material up to about 4 km (21–22 March), then explosions with a column more than 5 km high (22–23 March). Studies estimate about 10 km at its peak. The wind carried ash 15–20 km east. Smaller explosions, under 2 km high, blew ash to the south-west until 29 March. The particles, fountain height and the shape of the gray ash on the ground are illustrations that follow those directions and distances.
Standing in a town shows the same model at real size, with heights not exaggerated. You start at eye level in the town and can move anywhere, as on the table. Go more than about 2 km up and the daylight sky fades to the dark table background. Close to you the ground is drawn in 10 m steps with sharper satellite images, but the elevation data is about 30 m, so small bumps and buildings are missing. The lava is drawn 5 m thick, which is an estimate. Time runs at the same pace as the rest of the story, so the lava front moves much faster than it really did. The falling ash is an illustration.
Town labels are placed approximately. On the table, heights are exaggerated 1.5 times, and the column is drawn to the same scale.
Sources: INGV Osservatorio Vesuviano (opens in a new tab) · Geological Magazine reconstruction (opens in a new tab) · 1944 lava flow map (Journal of Maps) (opens in a new tab, PDF)
Versions
| Part | Version | What it is |
|---|---|---|
| App | VR story 0.12 | 0.12: sound on iPhone: the audio is started properly inside the tap, and a silent track loops while the eruption plays so the ring/silent switch does not mute it. 0.11: on a phone the sheet is more compact: smaller type and buttons, the date and the stage on one line, and the commentary under More; smaller credits. 0.10: works on a phone held upright: the panel becomes a sheet along the bottom with the model above it, "More" opens the rest of the controls, the AR button sits in the sheet, bigger touch targets, and the credits move to the top right. 0.9: “Photos and eyewitnesses” (the newsreels were removed from the shared archive, version 1.7, as both need a paid licence). 0.8: credits shortened to one line with a Sources list (exact data credits, “Powered by Esri”); © line removed; height note moved to the headset menu. 0.7: in a town, going more than about 2 km up fades the daylight sky and haze to the dark table background. 0.6: in a town you are no longer fixed to one spot: the mouse, wheel and keys work as on the table, starting at eye level, never below the ground. 0.5: standing in a town, the scroll wheel and + / − zoom in like binoculars, and right-drag looks around (both did nothing there). 0.4: accessibility (keyboard control of the model, screen-reader descriptions and announcements of each moment, contrast, focus outlines, all sections available on small screens and when zoomed) and credit tag. 0.3: the whole eruption plays without stopping (about 1½ minutes) as the moments change; afterwards Back and Next open each moment, and Play replays that part. 0.2: fixes from review (Play beats the automatic start, the first moment is before the eruption, model versions listed, text corrections). 0.1: Guided version of Vesuvius VR 0.4: the same eight moments as the 3D story, with Back, Play and Next on screen and on the headset menu. Each moment plays one part of the eruption, then waits for you. Sound starts off |
| Lava model | 1.0 | DOWNFLOW-style steepest descent with hollow filling (same code as the lava explorer), run for the two 1944 flows; lava drawn where at least 1 in 5 flows went |
| Lava look and timing | 0.1 | Cools from yellow-hot to a dark crust; one speed, timed so the northern flow reaches San Sebastiano early on 21 March. First numbered version |
| Ash cloud and fountains | 0.2 | Illustration: eight fountains up to about 4 km, an ash column over 5 km blown east, then bursts under 2 km blown south-west. 0.2: those bursts lowered from 3 km (INGV) |
| Ash on the ground | 0.1 | Illustration of the ash-fall areas east and south-west. First numbered version |
| Sound | 0.1 | Made in the browser, no recordings. Off until you turn it on |
| 1944 archive | – | Shared file from jsawle/curriculum_artifacts (vesuvius-1944-archive.js), also used by the 3D story. The eight moments come from this file too |