Hofsjökull
Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)
Status (automatic)
No particular signs of unrest in the last 24 hours — 0 earthquakes recorded, within the system's normal range. Volcano is in normal, non-eruptive state.
VONA = Volcano Observatory Notice for Aviation; the official Met Office colour code for aviation. Independent of Skjálfti's automatic analysis.
Large central volcano beneath the namesake glacier in the central highlands. No eruptions in historical time. (overview — more at vedur.is) · circle on the map = rough outline of the system (radius).
Subglacial system: a subglacial eruption can cause a jökulhlaup (sudden glacial meltwater flood) with little warning, and volcanic gases (incl. SO₂, CO₂) can be dangerous near vents and may pool in hollows. These are standing features of the system, not a sign of an imminent eruption.
📜 Did you know?
Beneath Hofsjökull lies the largest active central volcano in Iceland by area, with a large caldera under the south-western part of the ice cap. Even so, no eruption has occurred there in recorded history, the last effusive eruption being about 3,000–4,500 years ago. The glacier is the source of the Þjórsá, Iceland's longest river (about 230 km).
Points = earthquake locations in the selected window, coloured by magnitude: M3+ · M2+ · smaller (a sample if more than 800).
Earthquakes
0
Largest
–
M3,0+
0
Depth range
–
Earthquakes over time
Cumulative count · 0 earthquakes · count moment
Depth (0 km at top).
Not enough depth data.
Magnitude distribution
Earthquakes
0
Largest
–
M3,0+
0
Depth range
–
Earthquakes over time
Cumulative count · 0 earthquakes · count moment
Depth (0 km at top).
Not enough depth data.
Magnitude distribution
Earthquakes
1
Largest
M1.4
M3,0+
0
Depth range
3–3 km
Earthquakes over time
Cumulative count · 1 earthquakes · total moment ≈ M1.4 · count moment
Depth (0 km at top).
Not enough depth data.
Magnitude distribution
Earthquakes
1
Largest
M1.4
M3,0+
0
Depth range
3–3 km
Earthquakes over time
Cumulative count · 1 earthquakes · total moment ≈ M1.4 · count moment
Depth (0 km at top).
Not enough depth data.
Magnitude distribution
Earthquakes
6
Largest
M1.6
M3,0+
0
Depth range
0–9 km
Earthquakes over time
Cumulative count · 6 earthquakes · total moment ≈ M1.8 · count moment
Depth (0 km at top).
Magnitude distribution
Depth cross-sections — color by age (orange=newest, grey=older), point size by M. Rising cluster = possible magma intrusion.
Earthquakes
41
Largest
M2.4
M3,0+
0
Depth range
0–10 km
Earthquakes over time
Cumulative count · 41 earthquakes · total moment ≈ M2.8 · count moment
Depth (0 km at top). Grey: fixed depth.
Magnitude distribution
Depth cross-sections — color by age (orange=newest, grey=older), point size by M. Rising cluster = possible magma intrusion.
Earthquakes
83
Largest
M2.4
M3,0+
0
Depth range
0–19 km
Earthquakes over time
Cumulative count · 83 earthquakes · total moment ≈ M2.8 · count moment
Depth (0 km at top). Grey: fixed depth.
Magnitude distribution
Depth cross-sections — color by age (orange=newest, grey=older), point size by M. Rising cluster = possible magma intrusion.
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Earthquakes
207
Largest
M2.7
M3,0+
0
Depth range
0–20 km
Earthquakes over time
Cumulative count · 207 earthquakes · total moment ≈ M3.2 · count moment
Depth (0 km at top) — shallowing in the data (4.8→3.7 km). Grey: fixed depth.
Magnitude distribution
Depth cross-sections — color by age (orange=newest, grey=older), point size by M. Rising cluster = possible magma intrusion.
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Earthquakes
380
Largest
M3.2
M3.0+
2
Days with data
257
This is a reduced view: it is built from the daily aggregate (counts, moment, magnitude bands, depth histogram) rather than individual events. Map points, the depth scatter, cross-sections and the migration fit are therefore missing — they need each event's location and depth. Counts, total moment and the b-value are exact, not approximated.
Earthquakes over time
Cumulative count and moment
Total moment of all events in the window equals a single Mw 3.6
Magnitude distribution
<158
1–2162
2–342
3–42
≥40
Gutenberg-Richter b ≈ 1.14 ± 0.10 (i.e. likely 1.04–1.24, M≥1.7, n=88)
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Earthquakes
453
Largest
M3.2
M3.0+
2
Days with data
310
This is a reduced view: it is built from the daily aggregate (counts, moment, magnitude bands, depth histogram) rather than individual events. Map points, the depth scatter, cross-sections and the migration fit are therefore missing — they need each event's location and depth. Counts, total moment and the b-value are exact, not approximated.
Earthquakes over time
Cumulative count and moment
Total moment of all events in the window equals a single Mw 3.7
Magnitude distribution
<176
1–2207
2–352
3–42
≥40
Gutenberg-Richter b ≈ 1.18 ± 0.10 (i.e. likely 1.08–1.27, M≥1.7, n=111)
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Earthquakes
563
Largest
M3.2
M3.0+
3
Days with data
391
This is a reduced view: it is built from the daily aggregate (counts, moment, magnitude bands, depth histogram) rather than individual events. Map points, the depth scatter, cross-sections and the migration fit are therefore missing — they need each event's location and depth. Counts, total moment and the b-value are exact, not approximated.
Earthquakes over time
Cumulative count and moment
Total moment of all events in the window equals a single Mw 3.8
Magnitude distribution
<190
1–2280
2–374
3–43
≥40
Gutenberg-Richter b ≈ 1.14 ± 0.08 (i.e. likely 1.07–1.22, M≥1.7, n=161)
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Earthquakes
930
Largest
M3.7
M3.0+
16
Days with data
538
This is a reduced view: it is built from the daily aggregate (counts, moment, magnitude bands, depth histogram) rather than individual events. Map points, the depth scatter, cross-sections and the migration fit are therefore missing — they need each event's location and depth. Counts, total moment and the b-value are exact, not approximated.
Earthquakes over time
Cumulative count and moment
Total moment of all events in the window equals a single Mw 4.3
Magnitude distribution
<194
1–2419
2–3285
3–416
≥40
Gutenberg-Richter b ≈ 0.94 ± 0.03 (i.e. likely 0.91–0.97, M≥1.7, n=477)
Note: before February 2026 about half of events lacked an automatic magnitude, so magnitude-dependent figures (b-value, count of M≥X) under-count earlier periods — the catalogue is not homogeneous across this window. Cumulative moment is barely affected.
Depth is automatic and uncertain; earthquakes alone do not show magma movement — deformation (GPS) and gas are needed. Grey points: automatic fixed-depth values. b-value computed for M≥1.5 (automatic magnitudes make lower completeness unreliable). Preliminary data.
Earthquakes in the system
| Time (UTC) | Mag | Depth (km) | Area |
|---|---|---|---|
| 2026-09-09 05:50 | M1.4 | 3.0 | Other areas |
| 2026-08-11 02:13 | M0.8 | 8.8 | Other areas |
| 2026-08-10 12:04 | M1.1 | 0.2 | Other areas |
| 2026-08-10 12:02 | M1.6 | 3.0 | Other areas |
| 2026-08-05 01:40 | M1.0 | 3.8 | Other areas |
| 2026-06-14 17:39 | M1.0 | 5.8 | Other areas |
| 2026-06-08 03:34 | M1.1 | 8.0 | Other areas |
| 2026-06-07 15:15 | M1.2 | 7.5 | Other areas |
| 2026-05-21 12:31 | M1.8 | 2.4 | Other areas |
| 2026-05-18 20:42 | M1.3 | 2.3 | Other areas |
| 2026-05-18 20:40 | M2.0 | 3.0 | Other areas |
| 2026-05-18 20:40 | M1.9 | 1.1 | Other areas |
| 2026-05-18 08:21 | M0.6 | 0.9 | Other areas |
| 2026-05-18 08:13 | M0.9 | 0.4 | Other areas |
| 2026-05-17 23:47 | M1.5 | 4.6 | Other areas |
| 2026-05-17 22:30 | M1.7 | 3.1 | Other areas |
| 2026-05-17 15:08 | M1.4 | 3.4 | Other areas |
| 2026-05-17 13:46 | M0.9 | 6.2 | Other areas |
| 2026-05-17 12:55 | M1.3 | 7.2 | Other areas |
| 2026-05-03 06:52 | M1.7 | 1.3 | Other areas |
| 2026-05-01 03:28 | M0.7 | 1.6 | Other areas |
| 2026-04-30 23:59 | M1.7 | 3.2 | Other areas |
| 2026-04-30 20:44 | M1.7 | 3.5 | Other areas |
| 2026-04-30 05:05 | M0.7 | 3.4 | Other areas |
| 2026-04-30 04:24 | M2.2 | 3.5 | Other areas |
| 2026-04-26 00:14 | M2.1 | 2.9 | Other areas |
| 2026-04-26 00:07 | M2.4 | 2.0 | Other areas |
| 2026-04-23 21:24 | M1.1 | 3.6 | Other areas |
| 2026-04-23 21:06 | M1.4 | 1.0 | Other areas |
| 2026-04-21 23:25 | M1.4 | 3.8 | Other areas |
| 2026-04-20 20:09 | M1.0 | 0.0 | Other areas |
| 2026-04-16 22:29 | M0.9 | 2.2 | Other areas |
| 2026-04-16 15:55 | M0.8 | 3.6 | Other areas |
| 2026-04-10 11:11 | M0.8 | 3.1 | Other areas |
| 2026-04-10 11:10 | M0.9 | 5.2 | Other areas |
| 2026-04-09 08:52 | M1.2 | 9.7 | Other areas |
| 2026-03-30 06:58 | M1.0 | 4.6 | Other areas |
| 2026-03-30 02:51 | M1.3 | 3.2 | Other areas |
| 2026-03-26 04:28 | M1.1 | 6.7 | Other areas |
| 2026-03-26 03:33 | M1.9 | 3.8 | Other areas |
| 2026-03-18 21:41 | M1.6 | 3.6 | Other areas |
| 2026-03-02 02:41 | M0.8 | 0.0 | Other areas |
| 2026-03-02 02:40 | M0.7 | 18.2 | Other areas |
| 2026-03-02 02:40 | M0.4 | 0.0 | Other areas |
| 2026-02-25 04:38 | M0.7 | 9.3 | Other areas |
| 2026-02-23 09:50 | M0.9 | 12.4 | Other areas |
| 2026-02-17 15:05 | M1.3 | 7.8 | Other areas |
| 2026-02-14 22:37 | M0.9 | 2.1 | Other areas |
| 2026-01-15 17:41 | – | 3.3 | Other areas |
| 2026-01-07 08:07 | M0.8 | 2.6 | Other areas |
| 2026-01-01 19:22 | M1.3 | 2.8 | Other areas |
| 2025-12-18 17:57 | M1.6 | 19.0 | Other areas |
| 2025-12-13 16:50 | M1.2 | 1.1 | Other areas |
| 2025-12-13 08:10 | – | 3.5 | Other areas |
| 2025-12-11 06:04 | M1.7 | 2.2 | Other areas |
| 2025-12-11 06:04 | – | 8.2 | Other areas |
| 2025-11-27 00:36 | – | 10.4 | Other areas |
| 2025-11-17 13:31 | – | 3.5 | Other areas |
| 2025-11-13 01:39 | – | 9.3 | Other areas |
| 2025-11-07 17:33 | – | 11.8 | Other areas |
System journal
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skjalftar-hofsjokull2026-08-11 11:10:02 UTC
In the last 24 hours, 3 earthquakes were measured in the Hofsjökull system, which is a large central volcano under the glacier of the same name in the central highlands. This indicates an increase in activity, as the weekly average is 1 earthquake per day and the monthly average is 0 earthquakes per day. The activity is somewhat higher than usual for this area, with a β-value of 2.8 and a cumulative magnitude (Mw) of 1.5 in the last 48 hours. The largest earthquake was M1.4. Results are automatic preliminary results.What do the numbers mean — and what should I do?
β (swarm signal): how high activity is versus the area's 2-year average. β above 2 means an ongoing swarm. It measures activity, not a forecast of a large quake.
Cumulative moment (Mw): the combined energy of the quakes in the period. Uplift (GNSS): whether the ground is rising or sinking, mm per year — the data are a few weeks old. Some systems (e.g. Svartsengi) deform in steps during eruption cycles rather than at a steady annual rate.
Swarm character is computed for a whole volcanic belt, not a single system — it describes the belt, not necessarily this one system.
What should I do? This is automatic monitoring for information — not an official warning. Follow official information from the Icelandic Met Office and Civil Protection (112).