Prestahnúkur
Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)
Status (automatic)
No particular signs of unrest in the last 24 hours — 1 earthquake recorded, within the system's normal range.Depth — 3D and cross-section Prestahnúkur · last 90 days
Each dot is an earthquake, depth as the third dimension — Prestahnúkur, last 90 days. Drag the 3D view to rotate; point at a dot for details.
3D (rotatable) · depth ×2.5
Cross-section — distance along profile (km) vs depth (km)
Map (top view)
<24 klst2–7 dolderunconstrained depthsize ∝ magnitude (M)
⚠ Preliminary depths, unreliable (automatic Met Office solutions; depth often poorly constrained). events with unconstrained (default) depth shown as open rings — not real structure. For illustration, not analysis.
🕰️ Last eruption / event — ~1127 years ago
Hallmundarhraun (around 880–920) (~900). A large shield eruption at the northern end of the system shortly after settlement produced Hallmundarhraun, which covers about 240 km² and contains the Surtshellir lava cave; the lava flowed more than 50 km west.
Volcanic system on the southwestern edge of Langjökull in the Western Volcanic Zone. The central volcano is a rhyolite tuya. No eruptions in historical time; among the least active systems in Iceland. (overview — more at vedur.is) · circle on the map = rough outline of the system (radius).
📜 Did you know?
The central volcano Prestahnúkur is a rhyolite tuya that erupted up through the Ice Age glacier tens of thousands of years ago — a flat-topped peak that records the ice thickness at the time. A silicic (rhyolite) central volcano is unusual in the Western Volcanic Zone, which is otherwise mostly basaltic. No eruptions in historical time, and the system is among the least studied in Iceland.
Points = earthquake locations in the selected window, coloured by magnitude: M3+ · M2+ · smaller (a sample if more than 800).
Earthquakes
1
Largest
M0.4
M3,0+
0
Depth range
16–16 km
Earthquakes over time
Cumulative count · 1 earthquakes · total moment ≈ M0.4 · count moment
Depth (0 km at top).
Not enough depth data.
Magnitude distribution
Earthquakes
3
Largest
M1.1
M3,0+
0
Depth range
1–16 km
Earthquakes over time
Cumulative count · 3 earthquakes · total moment ≈ M1.3 · 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
16
Largest
M1.8
M3,0+
0
Depth range
0–16 km
Earthquakes over time
Cumulative count · 16 earthquakes · total moment ≈ M2.2 · 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
182
Largest
M2.8
M3,0+
0
Depth range
0–26 km
Earthquakes over time
Cumulative count · 182 earthquakes · total moment ≈ M3.1 · 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
1703
Largest
M3.9
M3,0+
6
Depth range
0–28 km
Earthquakes over time
Cumulative count · 1703 earthquakes · total moment ≈ M4.1 · 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.
Gutenberg-Richter b ≈ 1.53 ± 0.12 (i.e. likely 1.40–1.65, M≥1.7, n=228)
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
1871
Largest
M3.9
M3,0+
6
Depth range
0–28 km
Earthquakes over time
Cumulative count · 1871 earthquakes · total moment ≈ M4.1 · 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.
Gutenberg-Richter b ≈ 1.52 ± 0.12 (i.e. likely 1.40–1.64, M≥1.7, n=237)
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 |
|---|---|---|---|
| 2026-07-25 22:55 | M0.4 | 15.8 | Langjökull |
| 2026-07-25 03:16 | M1.1 | 9.2 | Other areas |
| 2026-07-25 01:12 | M1.0 | 0.9 | Other areas |
| 2026-07-24 08:27 | M1.5 | 3.0 | Langjökull |
| 2026-07-24 02:26 | M1.3 | 11.5 | Langjökull |
| 2026-07-24 00:00 | M1.7 | 0.0 | Langjökull |
| 2026-07-23 23:16 | M1.8 | 8.3 | Langjökull |
| 2026-07-23 22:46 | M1.5 | 6.6 | Langjökull |
| 2026-07-23 22:02 | M0.8 | 16.5 | Langjökull |
| 2026-07-23 21:37 | M0.8 | 16.4 | Langjökull |
| 2026-07-20 09:44 | M1.0 | 5.2 | Langjökull |
| 2026-07-20 04:59 | M0.9 | 0.8 | Langjökull |
| 2026-07-20 01:57 | M0.7 | 15.8 | Langjökull |
| 2026-07-20 00:41 | M1.1 | 5.5 | Langjökull |
| 2026-07-20 00:19 | M0.7 | 12.9 | Langjökull |
| 2026-07-19 20:21 | M1.5 | 5.2 | Langjökull |
| 2026-07-19 19:39 | M1.3 | 4.0 | Langjökull |
| 2026-07-19 18:16 | M1.3 | 4.1 | Langjökull |
| 2026-07-19 17:56 | M0.8 | 20.1 | Langjökull |
| 2026-07-19 17:46 | M1.3 | 6.9 | Langjökull |
| 2026-07-19 13:35 | M1.4 | 4.0 | Langjökull |
| 2026-07-19 03:45 | M0.4 | 16.2 | Langjökull |
| 2026-07-19 03:30 | M0.7 | 17.3 | Langjökull |
| 2026-07-18 21:28 | M1.5 | 3.3 | Langjökull |
| 2026-07-18 21:28 | M1.5 | 4.3 | Langjökull |
| 2026-07-18 06:44 | M0.9 | 5.5 | Other areas |
| 2026-07-17 20:57 | M1.1 | 5.0 | Other areas |
| 2026-07-17 14:16 | M0.9 | 18.9 | Langjökull |
| 2026-07-17 14:12 | M1.2 | 16.3 | Other areas |
| 2026-07-16 22:10 | M1.0 | 6.7 | Other areas |
| 2026-07-16 21:44 | M1.3 | 1.9 | Other areas |
| 2026-07-16 11:57 | M1.9 | 3.9 | Langjökull |
| 2026-07-15 07:47 | M1.4 | 5.2 | Other areas |
| 2026-07-14 18:20 | M1.7 | 1.1 | Other areas |
| 2026-07-13 22:58 | M1.9 | 4.3 | Langjökull |
| 2026-07-12 02:29 | M0.9 | 11.5 | Langjökull |
| 2026-07-12 02:29 | M1.2 | 9.7 | Langjökull |
| 2026-07-11 18:37 | M1.3 | 4.9 | Langjökull |
| 2026-07-11 18:14 | M1.4 | 3.6 | Langjökull |
| 2026-07-11 18:14 | M1.5 | 3.2 | Langjökull |
| 2026-07-11 06:29 | M1.4 | 11.4 | Langjökull |
| 2026-07-10 17:42 | M0.6 | 19.7 | Langjökull |
| 2026-07-09 08:56 | M1.4 | 5.2 | Langjökull |
| 2026-07-09 08:43 | M1.7 | 4.7 | Langjökull |
| 2026-07-09 08:43 | M1.8 | 3.6 | Langjökull |
| 2026-07-08 23:28 | M1.4 | 4.7 | Langjökull |
| 2026-07-08 23:28 | M1.4 | 0.0 | Langjökull |
| 2026-07-07 17:37 | M1.7 | 9.3 | Langjökull |
| 2026-07-07 17:37 | M1.2 | 18.8 | Langjökull |
| 2026-07-07 17:36 | M1.4 | 3.1 | Langjökull |
| 2026-07-07 17:36 | M1.0 | 21.9 | Other areas |
| 2026-07-07 07:50 | M0.7 | 0.0 | Other areas |
| 2026-07-07 07:49 | M1.4 | 5.5 | Other areas |
| 2026-07-07 07:48 | M1.4 | 5.4 | Other areas |
| 2026-07-07 07:48 | M1.6 | 5.5 | Other areas |
| 2026-07-07 04:48 | M0.6 | 9.0 | Other areas |
| 2026-07-07 04:48 | M1.3 | 10.9 | Other areas |
| 2026-07-06 08:45 | M1.4 | 3.5 | Langjökull |
| 2026-07-06 08:12 | M0.5 | 0.0 | Other areas |
| 2026-07-06 07:15 | M1.3 | 21.7 | Langjökull |
System journal
Automatic snapshots and media coverage, in chronological order. Subscribe: RSS · ntfy
skjalftar-prestahnukur2026-07-20 09:50:05 UTC
Over the last 24 hours, 11 earthquakes were detected in Prestahnúkur, a volcanic system at the southwestern margin of Langjökull which is among the least active systems in the country. This seismic activity is within what is considered normal for this area, though it is currently increasing as the last 24 hours are well above the weekly average rate. This represents scattered background activity rather than swarms, with 77% of events over the last seven days being independent, and the activity most closely resembles the period around June 14, 2025. The largest earthquake in the last 48 hours was magnitude 1.5 and the cumulative magnitude for that period was 2.0, though these results are automatic preliminary findings where depth is unreliable.2026-06-19 21:10:05 UTC
In the last 24 hours, 18 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area and consisting mostly of short-lived swarms. Activity is similar to the past week with a cumulative magnitude of Mw 2.5 and a b-value of 1.53. These are automatic preliminary results and the activity most closely resembles the period around May 20, 2026. Further charts and maps are available below.2026-06-19 13:00:07 UTC
In the last 24 hours, 19 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area but similar to the past week. The increase is mostly due to short-lived swarms, with the largest event being M2.0 and a cumulative magnitude of Mw 2.5 over the last 48 hours. These are automatic preliminary results and the activity most closely resembles the period around May 20, 2026. Further details on trends and maps are available below.2026-06-18 08:00:08 UTC
In the last 24 hours, 12 earthquakes were recorded in the Prestahnúkur system, a volcanic system at the southwestern edge of Langjökull, and activity is decreasing compared to the weekly average. Although the events are mostly short-lived swarms, activity is unusually high for this area, with a b-value of 1.54 and a cumulative magnitude of Mw 2.7 over the past 48 hours. The activity most closely resembles the period around May 17, 2026, and these figures are automatic preliminary results. Further charts and maps are available below.2026-06-16 19:05:05 UTC
In the last 24 hours, 27 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area but similar to the past week. The increase consists mostly of short-lived swarms, with the largest event being M2.0 and a cumulative magnitude of Mw 2.6 over the last 48 hours. Activity most closely resembles the period around May 17, 2026, though results are automatic preliminary data. Further charts and maps are available below.2026-06-14 19:10:04 UTC
In the last 24 hours, 13 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area and consisting mostly of short-lived swarms. Activity is similar to the past week, but these figures are automatic preliminary results with unreliable depth. This volcanic system at the southwestern margin of Langjökull is among the least active in the country, and current conditions most closely resemble the period around May 15, 2026. Further charts and maps are available below.2026-06-14 15:25:02 UTC
In the last 24 hours, 11 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area although similar to the past week. The increase is mostly due to short-lived swarms, with the largest event at M1.8 and a cumulative magnitude of Mw 2.0. These are automatic preliminary results and the activity most closely resembles the period around May 15, 2026. Further charts and maps are available below.2026-06-13 06:00:04 UTC
In the last 24 hours, 13 earthquakes were recorded in the Prestahnúkur system, indicating slightly higher activity than usual for this area but similar to the past week. The increase is mostly due to short-lived swarms, with the largest event being M2.3 and a cumulative magnitude of Mw 2.8 over the last 48 hours. Activity most closely resembles the period around May 14, 2026, though results are automatic preliminary results. Further details on trends and maps are available below.2026-06-12 17:21:26 UTC
In the last 24 hours, 64 earthquakes were recorded in the Prestahnúkur system and activity is increasing, though it remains within normal levels for this area. The increase consists mostly of short-lived swarms rather than distributed background activity and most closely resembles the period around May 13, 2026. The largest earthquake was M2.3 with a cumulative moment of Mw 2.8 over the past 48 hours, and results are automatic preliminary results. Further details on trends and maps can be found below.2026-06-11 19:55:04 UTC
In the last 24 hours, nine earthquakes were recorded in the Prestahnúkur system, a rhyolitic tuya and one of the least active systems in the country, with activity now decreasing although still higher than usual for this area. The recent increase is mostly due to short-lived swarms rather than distributed background seismicity and most closely resembles the period around May 12, 2026. The largest earthquake in the past 48 hours was M2.1 with a cumulative moment of Mw 2.3, while the b-value is 1.44 +/- 0.19. Results are automatic preliminary results, and further data can be found below.2026-06-11 17:35:04 UTC
In the last 24 hours, eight earthquakes were recorded in the Prestahnúkur system, a rhyolitic tuya and one of the least active volcanic systems in the country. Activity is decreasing compared to the weekly average but remains higher than usual for this area, with the increase consisting mostly of short-lived swarms. The largest earthquake in the past 48 hours was M2.1 with a cumulative magnitude of Mw 2.3, though results are automatic preliminary data. Current activity most closely resembles the period around May 12, 2026.Repeated × 3 since 2026-06-10 19:25:04 — last 2026-06-11 13:15:04
In the last 24 hours, five earthquakes were recorded in the Prestahnúkur system and activity is decreasing compared to the weekly average, though it remains normal for this area. The increase over the past week has consisted mostly of short-lived swarms rather than distributed background activity. The largest earthquake in the last 48 hours was M2.1 and the cumulative magnitude for the period is Mw 2.3. These figures are automatic preliminary results and the activity most closely resembles the period around May 12, 2026.2026-06-10 17:20:06 UTC
In the last 24 hours, seven earthquakes were recorded in the Prestahnúkur system, a rhyolitic tuya and one of the least active volcanic systems in the country. Activity is decreasing compared to the weekly average but remains higher than usual for this area, with the increase consisting mostly of short-lived swarms according to automatic preliminary results. The cumulative magnitude of the largest events in the last 48 hours was Mw 2.2, and the b-value was measured at 1.46 +/- 0.20. Current activity most closely resembles the period around May 11, 2026, while further data on trends and land uplift can be found lower on the page.2026-06-10 15:00:06 UTC
In the last 24 hours, eight earthquakes were recorded in the Prestahnúkur system, a rhyolitic tuya and one of the least active volcanic systems in the country. Activity is decreasing compared to the weekly average but remains higher than usual for this area, with the increase consisting mostly of short-lived swarms according to automatic preliminary results. The cumulative magnitude of the largest events in the last 48 hours was Mw 2.2, and the b-value was measured at 1.46 +/- 0.20. This activity most closely resembles the period around May 11, 2026, and further charts and plots are available below.2026-06-10 10:55:04 UTC
In the last 24 hours, nine earthquakes were recorded in the Prestahnúkur system and activity is decreasing although it remains higher than usual for this area. The increase consists mostly of short-lived swarms rather than distributed background activity, with the largest earthquake in the past 48 hours measuring M1.7. These automatic preliminary results most closely resemble the period around May 11, 2026, in terms of event frequency. Further details on trends and measurements are available below.2026-06-10 06:00:06 UTC
In the last 24 hours, 12 earthquakes were recorded in the Prestahnúkur system, a rhyolitic tuya and one of the least active systems in the country, where activity is now decreasing although still higher than usual for this area. The recent increase has consisted mostly of short-lived swarms rather than distributed background seismicity, with the largest earthquake in the past 48 hours measuring M1.7 and a cumulative moment of Mw 2.2. These figures are automatic preliminary results and most closely resemble the activity period around May 11, 2026, while further details on trends are available below.2026-06-10 03:20:04 UTC
In the last 24 hours, 14 earthquakes were recorded in the Prestahnúkur system and activity is decreasing although it remains higher than usual for this area. The increase is mostly due to short-lived swarms rather than distributed background activity, with the largest earthquake at M1.7 and a cumulative magnitude of Mw 2.3 in the past 48 hours. This automatic preliminary result most closely resembles the period around May 11, 2026, in terms of event frequency. Further details on trends and measurements are available below.2026-06-09 09:10:05 UTC
In the last 24 hours, 13 earthquakes were recorded in the Prestahnúkur system, indicating higher than usual activity for this area although it is decreasing compared to the weekly rate. The increase consists mostly of short-lived swarms and resembles the period around July 7, 2024, while the system remains one of the least active in the country. The cumulative magnitude over the last 48 hours was Mw 2.2 with a b-value of 1.39 +/- 0.18, and results are automatic preliminary results. Further charts and maps 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).