Prestahnúkur
Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)
Status (automatic)
In the last 24 hours, 5 earthquakes were measured in the Prestahnúkur system, which is a volcanic system at the southwestern edge of Langjökull. The activity is increasing and is now somewhat higher than usual in this area, resembling a period around May 30, 2008. The largest earthquake in the last 48 hours was M2.8, and the cumulative moment magnitude was Mw 2.9. The seismic activity is mostly diffuse background activity rather than swarms. These are automatic preliminary results. 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.
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
11
Largest
M2.8
M3,0+
0
Depth range
4–16 km
Earthquakes over time
Cumulative count · 11 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.
Earthquakes
13
Largest
M2.8
M3,0+
0
Depth range
4–16 km
Earthquakes over time
Cumulative count · 13 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.
Earthquakes
21
Largest
M2.8
M3,0+
0
Depth range
1–16 km
Earthquakes over time
Cumulative count · 21 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.
Earthquakes
54
Largest
M2.8
M3,0+
0
Depth range
0–17 km
Earthquakes over time
Cumulative count · 54 earthquakes · total moment ≈ M3.0 · count moment
Depth (0 km at top) — shallowing in the data (9.0→5.5 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.
Earthquakes
610
Largest
M3.3
M3,0+
2
Depth range
0–23 km
Earthquakes over time
Cumulative count · 610 earthquakes · total moment ≈ M3.6 · 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 ≈ 1.29 ± 0.15 (i.e. likely 1.14–1.44, M≥1.7, n=72)
Earthquakes
1412
Largest
M3.9
M3,0+
4
Depth range
0–28 km
Earthquakes over time
Cumulative count · 1412 earthquakes · total moment ≈ M4.1 · count moment
Depth (0 km at top) — shallowing in the data (8.6→5.2 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.
Gutenberg-Richter b ≈ 1.35 ± 0.13 (i.e. likely 1.22–1.48, M≥1.7, n=147)
Earthquakes
1483
Largest
M3.9
M3,0+
4
Depth range
0–28 km
Earthquakes over time
Cumulative count · 1483 earthquakes · total moment ≈ M4.1 · count moment
Depth (0 km at top) — shallowing in the data (8.4→5.2 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.
Gutenberg-Richter b ≈ 1.37 ± 0.13 (i.e. likely 1.25–1.50, M≥1.7, n=158)
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
1641
Largest
M3.9
M3,0+
4
Depth range
0–28 km
Earthquakes over time
Cumulative count · 1641 earthquakes · total moment ≈ M4.1 · count moment
Depth (0 km at top) — shallowing in the data (8.0→5.2 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.
Gutenberg-Richter b ≈ 1.36 ± 0.12 (i.e. likely 1.24–1.48, M≥1.7, n=165)
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
2.019
Largest
M4.1
M3.0+
5
Days with data
443
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
<1711
1–21040
2–378
3–44
≥41
Gutenberg-Richter b ≈ 1.32 ± 0.09 (i.e. likely 1.22–1.41, M≥1.7, n=235)
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
2.620
Largest
M4.1
M3.0+
8
Days with data
704
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 4.4
Magnitude distribution
<1804
1–21457
2–3166
3–47
≥41
Gutenberg-Richter b ≈ 1.21 ± 0.06 (i.e. likely 1.15–1.27, M≥1.7, n=406)
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
3.640
Largest
M4.3
M3.0+
24
Days with data
1.041
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 4.7
Magnitude distribution
<1956
1–22175
2–3300
3–421
≥43
Gutenberg-Richter b ≈ 1.07 ± 0.04 (i.e. likely 1.03–1.11, M≥1.7, n=687)
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
4.711
Largest
M4.5
M3.0+
50
Days with data
1.378
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 4.9
Magnitude distribution
<11124
1–22870
2–3479
3–446
≥44
Gutenberg-Richter b ≈ 1.02 ± 0.03 (i.e. likely 0.99–1.05, M≥1.7, n=1083)
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 |
|---|---|---|---|
| 2026-09-11 19:10 | M1.1 | 5.3 | Langjökull |
| 2026-09-11 19:02 | M1.0 | 5.5 | Langjökull |
| 2026-09-11 18:54 | M0.6 | 11.0 | Langjökull |
| 2026-09-11 18:41 | M0.9 | 5.0 | Langjökull |
| 2026-09-11 18:22 | M0.8 | 12.4 | Langjökull |
| 2026-09-11 18:21 | M1.4 | 4.3 | Langjökull |
| 2026-09-11 18:19 | M1.4 | 16.4 | Langjökull |
| 2026-09-11 18:12 | M1.3 | 9.0 | Langjökull |
| 2026-09-11 18:11 | M2.3 | 4.5 | Langjökull |
| 2026-09-11 18:10 | M2.8 | 3.8 | Langjökull |
| 2026-09-11 17:36 | M2.3 | 4.7 | Langjökull |
| 2026-09-10 03:34 | M1.2 | 10.9 | Langjökull |
| 2026-09-09 23:45 | M1.6 | 6.1 | Langjökull |
| 2026-09-09 04:56 | M1.1 | 5.0 | Langjökull |
| 2026-09-09 01:59 | M1.0 | 6.1 | Langjökull |
| 2026-09-08 18:56 | M0.6 | 3.2 | Langjökull |
| 2026-09-07 15:16 | M1.6 | 15.0 | Langjökull |
| 2026-09-07 02:44 | M1.0 | 12.8 | Langjökull |
| 2026-09-06 12:02 | M0.8 | 0.6 | Other areas |
| 2026-09-06 09:45 | M1.2 | 5.3 | Langjökull |
| 2026-09-06 02:53 | M0.9 | 5.4 | Langjökull |
| 2026-09-04 17:28 | M1.2 | 16.0 | Langjökull |
| 2026-09-02 20:11 | M1.5 | 14.1 | Langjökull |
| 2026-09-01 16:33 | M0.7 | 10.0 | Langjökull |
| 2026-09-01 15:55 | M0.6 | 0.4 | Other areas |
| 2026-09-01 02:43 | M1.2 | 0.0 | Langjökull |
| 2026-09-01 02:32 | M1.0 | 8.4 | Langjökull |
| 2026-08-31 23:15 | M1.8 | 4.7 | Langjökull |
| 2026-08-31 23:06 | M1.2 | 6.6 | Langjökull |
| 2026-08-31 16:36 | M1.2 | 9.0 | Langjökull |
| 2026-08-31 15:26 | M1.4 | 4.4 | Langjökull |
| 2026-08-31 15:23 | M2.4 | 3.4 | Langjökull |
| 2026-08-31 12:36 | M0.8 | 13.0 | Langjökull |
| 2026-08-31 05:16 | M1.3 | 5.1 | Langjökull |
| 2026-08-31 01:11 | M0.7 | 5.0 | Langjökull |
| 2026-08-29 08:38 | M1.4 | 13.3 | Langjökull |
| 2026-08-28 10:56 | M1.5 | 6.1 | Langjökull |
| 2026-08-28 04:04 | M0.9 | 13.3 | Langjökull |
| 2026-08-27 21:59 | M1.2 | 2.4 | Langjökull |
| 2026-08-27 16:16 | M1.7 | 0.0 | Langjökull |
| 2026-08-26 07:42 | M1.2 | 12.9 | Langjökull |
| 2026-08-23 23:53 | M1.0 | 9.4 | Langjökull |
| 2026-08-23 07:16 | M0.9 | 16.1 | Langjökull |
| 2026-08-22 09:06 | M0.9 | 12.8 | Langjökull |
| 2026-08-21 18:13 | M0.8 | 12.2 | Langjökull |
| 2026-08-21 07:09 | M0.2 | 16.6 | Langjökull |
| 2026-08-21 01:50 | M0.7 | 3.4 | Langjökull |
| 2026-08-21 01:25 | M1.1 | 4.4 | Langjökull |
| 2026-08-19 03:53 | M0.7 | 16.7 | Other areas |
| 2026-08-18 17:19 | M1.5 | 4.2 | Langjökull |
| 2026-08-17 04:00 | M0.5 | 15.3 | Other areas |
| 2026-08-17 02:20 | M0.6 | 15.4 | Langjökull |
| 2026-08-15 14:55 | M0.9 | 6.1 | Langjökull |
| 2026-08-15 03:46 | M0.7 | 14.4 | Langjökull |
| 2026-08-12 03:38 | M0.7 | 16.3 | Langjökull |
| 2026-08-11 06:20 | M1.4 | 7.4 | Langjökull |
| 2026-08-10 19:06 | M0.9 | 7.2 | Langjökull |
| 2026-08-10 10:34 | M0.9 | 17.8 | Langjökull |
| 2026-08-10 00:55 | M0.4 | 15.2 | Langjökull |
| 2026-08-09 11:05 | M0.8 | 16.2 | Langjökull |
System journal
Automatic snapshots and media coverage, in chronological order. Subscribe: RSS · ntfy
skjalftar-prestahnukur2026-09-11 18:15:02 UTC
In the last 24 hours, 3 earthquakes were measured in the Prestahnúkur system, which is a volcanic system at the southwestern edge of Langjökull. Activity is increasing, but is still within what is normal for this area. The largest earthquake in the last 48 hours was M2.8 and the cumulative moment of earthquakes in the same period was Mw 2.9. The activity is diffuse background activity rather than swarms and is most similar to a period around May 30, 2008. These are automatic preliminary results.2026-09-10 03:40:02 UTC
In the last 24 hours, 3 earthquakes were measured at Prestahnúkur, a volcanic system on the southwest edge of Langjökull. Activity is increasing and is somewhat higher than usual in this area, which is among the least active systems in the country. The largest earthquake in the last 48 hours was M2.0, and the cumulative moment magnitude for the same period was Mw2.0. The activity is diffuse background seismicity rather than swarms and most resembles a period around December 20, 2015. These are automatic preliminary results.Repeated × 3 since 2026-09-09 05:00:03 — last 2026-09-09 23:50:05
In the last 24 hours, 3 earthquakes were measured in the Prestahnúkur system, which is a volcanic system on the southwestern edge of Langjökull. This is an increase in activity, as the last 24 hours are well above the weekly average. The largest earthquake in the last 48 hours was M2.0 and the cumulative moment of earthquakes during the same period was Mw 2.0. The seismic activity is diffuse background activity rather than swarms and is within what is normal for this area, which is among the least active systems in the country. Results are automatic preliminary results and depth is unreliable. The activity is most similar to a period around April 10, 2026, when 10 earthquakes were measured.Repeated × 2 since 2026-09-07 02:50:03 — last 2026-09-07 08:20:02
Over the last 24 hours, 3 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 activity is similar to the past week and is considered slightly higher than usual for this area, characterized by scattered background activity rather than swarms, with 79% of events over the last 7 days being independent. The largest earthquake in the last 48 hours was magnitude 1.2 and the cumulative magnitude for the period was Mw 1.4, though these results are unverified automatic preliminary data with unreliable depth. The current activity resembles the period around October 14, 2010, when 10 earthquakes were detected, and further details and maps of the area can be found below.2026-09-01 09:25:04 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 activity is increasing, as the last 24 hours are well above the weekly average, though the earthquake activity remains within what is considered normal for this area and is characterized by scattered background activity rather than swarms. The largest earthquake in the last 48 hours was magnitude 2.4, with a cumulative moment magnitude of 2.5 during the period, though these results are automatic preliminary findings where depth is unreliable. The current activity most closely resembles the period around 28 May 2026 as a historical analogue, and further details and maps of the area can be found below.2026-09-01 02:50:05 UTC
In the last 24 hours, 11 earthquakes were recorded in the Prestahnúkur system, representing an increase above the weekly average and higher activity than usual for this area. The activity is characterized by distributed background seismicity rather than swarms and most closely resembles a period around July 13, 2026. The largest earthquake in the past 48 hours was M2.4 with a cumulative moment of Mw 2.5. Results are automatic preliminary results, and further data can be found below on the page.2026-08-03 19:05:05 UTC
Over the last 24 hours, 12 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 activity is increasing and is somewhat higher than usual for this area, characterized by scattered background activity rather than swarms, as 61% of the events over the last seven days were independent. The largest earthquake in the last 48 hours was magnitude 1.8 and the cumulative magnitude for that period was 2.1, though these are unverified automatic preliminary results where depth is unreliable. The current activity most closely resembles the period around June 16, 2025, when 15 earthquakes were detected, and further information and maps can be found lower on the page.Repeated × 2 since 2026-07-20 09:50:05 — last 2026-08-03 10:35:04
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 activity is increasing, as the last 24 hours are well above the weekly average of 3 earthquakes per day, though the seismic activity remains within what is considered normal for this area. This represents scattered background activity rather than swarms, with 62% of events over the last 7 days being independent, and the situation most closely resembles the period around 15 June 2025 when 14 earthquakes were detected. The largest earthquake in the last 48 hours was magnitude 1.8 and the cumulative moment magnitude for the period was 2.1, 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.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).