Fagradalsfjall
Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)
Status (automatic)
No particular signs of unrest in the last 24 hours — 5 earthquakes recorded, within the system's normal range.VONA = Volcano Observatory Notice for Aviation; the official Met Office colour code for aviation. Independent of Skjálfti's automatic analysis.
🕰️ Last eruption / event — 3 years ago
Litli-Hrútur (3rd Fagradalsfjall eruption) (2023-07-10). Activity shifted NW from Fagradalsfjall to the Sundhnúkur fissure system in Oct 2023.
Volcanic system in the central Reykjanes Peninsula. Erupted in 2021, 2022 and 2023 (Geldingadalir, Meradalir, Litli-Hrútur) — the first eruptions on the peninsula in ~800 years. (overview — more at vedur.is) · circle on the map = rough outline of the system (radius).
📜 Did you know?
Fagradalsfjall itself had been dormant for about 6000 years before the 2021 eruption. The Reykjanes Peninsula as a whole had been quiet for ~800 years (since the Reykjaneseldar of 1210-1240); models suggest a new 200-300 year active cycle.
Historical eruptions in the system — points colored by size, blue circle shows where we are now in time.
☁ Air quality — SO₂
Real-time SO₂ from Environment Agency (2026-07-26T20:00 UTC). Yellow > 20 µg/m³, orange > 125 (health threshold), red > 350. Nearest stations to this system; past 24h shown for the highest.
Grindavík11.7 µg/m³
Hafnarfjörður (Hvaleyrarholt)7.5 µg/m³
Vogar4.5 µg/m³
Ásbrú (Keflavík)3.5 µg/m³
Keflavík (Vatnaveröld)2.5 µg/m³
Points = earthquake locations in the selected window, coloured by magnitude: M3+ · M2+ · smaller (a sample if more than 800).
Earthquakes
5
Largest
M-0.4
M3,0+
0
Depth range
0–12 km
Earthquakes over time
Cumulative count · 5 earthquakes · total moment ≈ M-0.2 · 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
6
Largest
M-0.4
M3,0+
0
Depth range
0–12 km
Earthquakes over time
Cumulative count · 6 earthquakes · total moment ≈ M-0.2 · 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
11
Largest
M-0.4
M3,0+
0
Depth range
0–12 km
Earthquakes over time
Cumulative count · 11 earthquakes · total moment ≈ M-0.1 · 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
43
Largest
M0.1
M3,0+
0
Depth range
0–16 km
Earthquakes over time
Cumulative count · 43 earthquakes · total moment ≈ M0.6 · 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.
Earthquakes
316
Largest
M1.8
M3,0+
0
Depth range
0–16 km
Earthquakes over time
Cumulative count · 316 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.
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
5947
Largest
M3.4
M3,0+
4
Depth range
0–16 km
Earthquakes over time
Cumulative count · 5947 earthquakes · total moment ≈ M3.9 · 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.
Gutenberg-Richter b ≈ 1.25 ± 0.07 (i.e. likely 1.18–1.32, M≥1.7, n=242)
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.
🌊 Volcanic tremor — Baseline volcanic tremor is currently normal, with variations fully explained by moderate…
IMO tremor plot (station vog). Most of the signal is weather and surf — not eruption confirmation. All stations: vedur.is ↗.
Weather now: wind 4 m/s (Fagradals-Hagafelli), waves 1.3 m — moderate.
Baseline volcanic tremor is currently normal, with variations fully explained by moderate local wind and ocean wave activity. (AI)
Band analysis past 9 days (from digitized RSAM values). High 2-4 Hz + low 0.5-1 Hz = possible magma-movement signal; high 0.5-1 Hz without 2-4 Hz = weather/surf.
Earthquakes in the system
| Time (UTC) | Mag | Depth (km) | Area |
|---|---|---|---|
| 2026-07-26 18:04 | M-0.6 | 11.7 | Reykjanesskagi Grindavík |
| 2026-07-26 11:46 | M-1.1 | 11.5 | Reykjanesskagi |
| 2026-07-26 11:14 | M-0.6 | 9.6 | Reykjanesskagi |
| 2026-07-26 11:13 | M-0.4 | 11.2 | Reykjanesskagi |
| 2026-07-26 05:54 | M-1.3 | 0.0 | Reykjanesskagi |
| 2026-07-25 10:12 | M-1.5 | 5.2 | Reykjanesskagi |
| 2026-07-24 11:21 | M-0.9 | 7.2 | Reykjanesskagi |
| 2026-07-21 20:47 | M-1.3 | 0.0 | Reykjanesskagi |
| 2026-07-20 04:39 | M-1.4 | 10.5 | Reykjanesskagi |
| 2026-07-20 04:37 | M-0.9 | 10.3 | Reykjanesskagi |
| 2026-07-20 00:56 | M-0.7 | 0.0 | Reykjanesskagi |
| 2026-07-19 08:36 | M-0.2 | 0.6 | Reykjanesskagi |
| 2026-07-19 04:20 | M-1.1 | 10.4 | Reykjanesskagi |
| 2026-07-18 20:53 | M-0.6 | 0.0 | Reykjanesskagi |
| 2026-07-17 09:18 | M-1.5 | 7.7 | Reykjanesskagi Grindavík |
| 2026-07-16 21:59 | M-0.6 | 3.7 | Reykjanesskagi |
| 2026-07-16 21:58 | M-1.2 | 9.3 | Reykjanesskagi |
| 2026-07-15 01:25 | M-0.7 | 2.8 | Reykjanesskagi |
| 2026-07-14 16:30 | M-1.1 | 6.3 | Reykjanesskagi Grindavík |
| 2026-07-09 21:08 | M-0.5 | 10.2 | Reykjanesskagi |
| 2026-07-09 21:08 | M-1.3 | 11.8 | Reykjanesskagi |
| 2026-07-08 20:02 | M-1.4 | 11.7 | Reykjanesskagi |
| 2026-07-08 07:19 | M-0.7 | 6.0 | Reykjanesskagi |
| 2026-07-08 05:51 | M-0.6 | 11.3 | Reykjanesskagi |
| 2026-07-08 05:51 | M-1.6 | 13.1 | Reykjanesskagi |
| 2026-07-08 05:50 | M-0.7 | 10.0 | Reykjanesskagi |
| 2026-07-08 05:50 | M-0.6 | 9.8 | Reykjanesskagi |
| 2026-07-05 02:19 | M-0.9 | 1.1 | Reykjanesskagi |
| 2026-07-04 17:36 | M-0.3 | 16.1 | Reykjanesskagi |
| 2026-07-04 12:26 | M-0.9 | 13.3 | Reykjanesskagi |
| 2026-07-04 11:22 | M-0.1 | 5.3 | Reykjanesskagi |
| 2026-07-03 14:18 | M-0.4 | 0.1 | Reykjanesskagi |
| 2026-07-03 00:59 | M-0.7 | 0.0 | Reykjanesskagi |
| 2026-07-03 00:20 | M-0.3 | 0.0 | Reykjanesskagi Grindavík |
| 2026-07-03 00:04 | M-0.2 | 10.9 | Reykjanesskagi |
| 2026-07-02 22:48 | M-0.8 | 6.0 | Reykjanesskagi |
| 2026-06-29 23:40 | M-0.6 | 10.7 | Reykjanesskagi |
| 2026-06-29 06:29 | M0.1 | 5.9 | Reykjanesskagi Grindavík |
| 2026-06-29 06:29 | M-0.3 | 5.7 | Reykjanesskagi Grindavík |
| 2026-06-29 00:59 | M-2.2 | 5.2 | Reykjanesskagi |
| 2026-06-28 16:10 | M-0.8 | 0.0 | Reykjanesskagi |
| 2026-06-27 22:00 | M-0.7 | 1.3 | Reykjanesskagi |
| 2026-06-27 22:00 | M-1.0 | 3.8 | Reykjanesskagi |
| 2026-06-24 02:12 | M-1.3 | 0.0 | Reykjanesskagi |
| 2026-06-23 02:57 | M-1.3 | 10.6 | Reykjanesskagi |
| 2026-06-23 02:39 | M-1.2 | 0.2 | Reykjanesskagi Grindavík |
| 2026-06-23 01:28 | M-0.3 | 0.3 | Reykjanesskagi |
| 2026-06-22 22:13 | M-2.4 | 3.6 | Reykjanesskagi |
| 2026-06-22 07:16 | M-1.7 | 5.2 | Reykjanesskagi |
| 2026-06-22 00:05 | M-1.5 | 8.0 | Reykjanesskagi |
| 2026-06-22 00:04 | M-1.1 | 0.0 | Reykjanesskagi |
| 2026-06-21 23:50 | M-0.9 | 7.0 | Reykjanesskagi Grindavík |
| 2026-06-21 19:39 | M-0.5 | 12.6 | Reykjanesskagi |
| 2026-06-21 05:47 | M-0.7 | 0.4 | Reykjanesskagi |
| 2026-06-21 05:16 | M-1.0 | 0.0 | Reykjanesskagi |
| 2026-06-21 00:59 | M-1.5 | 1.1 | Reykjanesskagi |
| 2026-06-21 00:59 | M-1.6 | 1.1 | Reykjanesskagi |
| 2026-06-21 00:47 | M-0.7 | 1.4 | Reykjanesskagi |
| 2026-06-20 01:28 | M-1.2 | 0.0 | Reykjanesskagi Grindavík |
| 2026-06-20 01:01 | M-1.4 | 2.3 | Reykjanesskagi Grindavík |
For the advanced — expert charts — Coulomb, migration, InSAR
🔬 Coulomb stress transfer — advanced analysis
4 earthquakes M≥3.0 in this window on this system. Such events transfer stress to neighbouring faults — some become more likely to slip, others less ("Coulomb stress transfer"). The Met Office does not publish focal mechanisms for automatically located events, so Skjálfti does not compute this itself — it requires strike/dip/rake data which is only available for M≥4.5 events in the GCMT catalogue.
For Coulomb analysis, see: USGS Coulomb 3.4 (stand-alone software) and focal mechanisms for Iceland in Global CMT.
For Coulomb analysis, see: USGS Coulomb 3.4 (stand-alone software) and focal mechanisms for Iceland in Global CMT.
📡 InSAR — radar deformation across the area
InSAR is satellite radar from Sentinel-1: it measures deformation across the whole area, not just points like GNSS stations. Six-day interferograms reveal where the ground rose or subsided between passes. InSAR distinguishes vertical deformation (magma chamber inflation) from horizontal (dike intrusion) — GNSS alone cannot.
View latest interferograms and time-series at COMET LiCS portal (Sentinel-1, ~4-6 day lag).
View latest interferograms and time-series at COMET LiCS portal (Sentinel-1, ~4-6 day lag).
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).