Grímsnes
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.
Small volcanic system in the Árnessýsla lowlands (crater rows such as Kerið and Seyðishólar). Last erupted ~5500 years ago. (overview — more at vedur.is) · circle on the map = rough outline of the system (radius).
📜 Did you know?
Grímsnes is a basaltic crater group in South Iceland — the youngest volcanism of the Western Volcanic Zone — with about a dozen short Holocene eruptions roughly 5,000–9,000 years ago. The best known is Kerið, a deep red-walled crater now holding a lake, alongside the scoria craters of Seyðishólar.
Historical eruptions in the system — points colored by size, blue circle shows where we are now in time.
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
5
Largest
M1.1
M3,0+
0
Depth range
0–8 km
Earthquakes over time
Cumulative count · 5 earthquakes · total moment ≈ M1.2 · 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
14
Largest
M1.3
M3,0+
0
Depth range
0–8 km
Earthquakes over time
Cumulative count · 14 earthquakes · total moment ≈ M1.5 · 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
41
Largest
M1.4
M3,0+
0
Depth range
0–12 km
Earthquakes over time
Cumulative count · 41 earthquakes · total moment ≈ M1.8 · 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
224
Largest
M2.6
M3,0+
0
Depth range
0–12 km
Earthquakes over time
Cumulative count · 224 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
335
Largest
M2.6
M3,0+
0
Depth range
0–15 km
Earthquakes over time
Cumulative count · 335 earthquakes · total moment ≈ M2.9 · 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
582
Largest
M2.6
M3,0+
0
Depth range
0–15 km
Earthquakes over time
Cumulative count · 582 earthquakes · total moment ≈ M2.9 · 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
1.636
Largest
M3.1
M3.0+
1
Days with data
651
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 3.3
Magnitude distribution
<11194
1–2168
2–311
3–41
≥40
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
3.651
Largest
M3.4
M3.0+
2
Days with data
1.299
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
<12919
1–2411
2–357
3–42
≥40
Gutenberg-Richter b ≈ 1.01 ± 0.08 (i.e. likely 0.93–1.10, M≥1.7, n=107)
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
10.154
Largest
M4.4
M3.0+
34
Days with data
2.920
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 4.6
Magnitude distribution
<18430
1–21253
2–3163
3–432
≥42
Gutenberg-Richter b ≈ 0.82 ± 0.04 (i.e. likely 0.78–0.86, M≥1.7, n=347)
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
22.879
Largest
M6.6
M3.0+
77
Days with data
5.653
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 6.6
Magnitude distribution
<118874
1–23185
2–3446
3–467
≥410
Gutenberg-Richter b ≈ 0.81 ± 0.03 (i.e. likely 0.78–0.84, M≥1.7, n=897)
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 17:04 | M1.1 | 0.1 | Other areas |
| 2026-09-09 12:23 | M0.5 | 0.0 | Other areas |
| 2026-09-07 22:57 | M-0.4 | 6.0 | Other areas |
| 2026-09-07 05:42 | M0.1 | 7.7 | Other areas |
| 2026-09-05 08:11 | M0.5 | 5.8 | Other areas |
| 2026-09-04 17:00 | M0.5 | 2.3 | Other areas |
| 2026-09-01 21:57 | M0.8 | 6.7 | Other areas |
| 2026-08-28 17:02 | M0.4 | 0.0 | Other areas |
| 2026-08-26 12:02 | M0.4 | 0.6 | Other areas |
| 2026-08-21 17:12 | M1.3 | 0.7 | Other areas |
| 2026-08-19 04:22 | M0.7 | 1.1 | Other areas |
| 2026-08-15 21:55 | M0.7 | 5.2 | Other areas |
| 2026-08-15 05:04 | M-0.1 | 7.1 | Other areas |
| 2026-08-14 20:04 | M-0.2 | 3.7 | Other areas |
| 2026-08-10 16:37 | M0.9 | 7.7 | Other areas |
| 2026-08-08 20:14 | M0.6 | 9.2 | Other areas |
| 2026-08-07 02:32 | M0.9 | 5.8 | Other areas |
| 2026-08-07 00:55 | M0.0 | 6.2 | Other areas |
| 2026-08-02 00:55 | M-0.0 | 3.0 | Other areas |
| 2026-07-28 17:06 | M0.5 | 0.2 | Other areas |
| 2026-07-27 19:20 | M-0.0 | 6.0 | Other areas |
| 2026-07-21 04:50 | M0.2 | 6.9 | Other areas |
| 2026-07-19 13:39 | M1.1 | 3.2 | Other areas |
| 2026-07-19 13:21 | M1.1 | 2.1 | Other areas |
| 2026-07-19 10:55 | M1.4 | 1.5 | Other areas |
| 2026-07-17 20:49 | M-0.3 | 5.2 | Other areas |
| 2026-07-17 18:20 | M0.9 | 3.4 | Other areas |
| 2026-07-15 09:19 | M0.3 | 6.0 | Other areas |
| 2026-07-15 09:15 | M0.6 | 6.1 | Other areas |
| 2026-07-15 09:09 | M0.3 | 7.6 | Other areas |
| 2026-07-15 09:06 | M0.5 | 5.4 | Other areas |
| 2026-07-14 20:21 | M0.2 | 6.1 | Other areas |
| 2026-07-14 20:17 | M0.6 | 5.7 | Other areas |
| 2026-07-10 15:53 | M0.5 | 12.0 | Other areas |
| 2026-07-10 12:01 | M0.6 | 0.0 | Other areas |
| 2026-07-09 09:33 | M0.5 | 3.9 | Other areas |
| 2026-07-04 19:02 | M0.8 | 6.7 | Other areas |
| 2026-06-27 17:48 | M0.4 | 5.6 | Other areas |
| 2026-06-23 09:45 | M0.1 | 5.9 | Other areas |
| 2026-06-19 12:12 | M0.4 | 6.3 | Other areas |
| 2026-06-15 22:05 | M0.3 | 4.0 | Other areas |
| 2026-06-10 20:52 | M0.4 | 5.3 | Other areas |
| 2026-06-10 13:11 | M0.4 | 5.2 | Other areas |
| 2026-06-08 09:50 | M0.0 | 6.4 | Other areas |
| 2026-06-05 18:29 | M0.6 | 5.4 | Other areas |
| 2026-06-05 18:29 | M0.8 | 5.0 | Other areas |
| 2026-06-04 22:59 | M0.7 | 6.8 | Other areas |
| 2026-06-03 02:12 | M-0.5 | 0.3 | Other areas |
| 2026-06-01 06:31 | M0.2 | 6.1 | Other areas |
| 2026-05-30 06:10 | M0.1 | 6.3 | Other areas |
| 2026-05-28 02:12 | M0.4 | 3.9 | Other areas |
| 2026-05-23 17:20 | M0.4 | 5.5 | Other areas |
| 2026-05-23 17:18 | M0.5 | 7.6 | Other areas |
| 2026-05-19 01:18 | M0.3 | 7.4 | Other areas |
| 2026-05-18 19:58 | M0.3 | 4.4 | Other areas |
| 2026-05-17 07:52 | M0.3 | 7.3 | Other areas |
| 2026-05-13 22:23 | M0.3 | 4.9 | Other areas |
| 2026-05-12 03:56 | M0.7 | 3.2 | Other areas |
| 2026-05-07 02:55 | M1.2 | 5.6 | Other areas |
| 2026-05-05 12:03 | M0.6 | 1.1 | Other areas |
System journal
Automatic snapshots and media coverage, in chronological order. Subscribe: RSS · ntfy
skjalftar-grimsnes2026-06-04 02:15:12 UTC
In the last 24 hours, three earthquakes were recorded in the Grímsnes system, a small volcanic system in the Árnessýsla uplands, with activity similar to the past week but slightly higher than usual for this area. The increase is mostly due to short-lived swarms rather than distributed background activity, with a β-value of 1.8 and a cumulative magnitude of Mw 2.1. These automatic preliminary results most closely resemble the period around October 14, 2025, and further details on trends are available below.Repeated × 2 since 2026-06-03 11:10:16 — last 2026-06-03 13:40:15
In the last 24 hours, four earthquakes were recorded in the Grímsnes system, a small volcanic system in the Árnessýsla uplands, with activity now increasing and higher than usual for this area. The increase is mainly due to short-lived swarms rather than distributed background activity, with a β-value of 1.8 and the largest earthquake measuring M2.1. These automatic preliminary results most closely resemble the period around October 14, 2025, in terms of event frequency. Further details on trends and measurements are available below.2026-06-01 22:20:15 UTC
In the last 24 hours, six earthquakes were recorded in the Grímsnes system, a small volcanic system in the Árnessýsla highlands, with activity now increasing and higher than usual for this area. The increase is characterized by distributed background activity rather than swarms and most closely resembles the period around June 26, 2024. The largest earthquake was M1.8 and the cumulative magnitude over 48 hours was Mw 1.9; these figures are automatic preliminary results. Further details on trends and maps can be found below.2026-06-01 18:45:09 UTC
In the last 24 hours, five earthquakes were recorded in the Grímsnes system, a small volcanic system in the Árnessýsla uplands, and activity is increasing although it remains within normal levels for this area. The increase is characterized by distributed background activity rather than distinct swarms and most closely resembles the period around June 28, 2024. The largest earthquake was M1.8 and the cumulative magnitude over the last 48 hours is Mw 1.9 according to automatic preliminary results. Further details on trends and measurements are available below.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).