Tjörnes / Grímsey
Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)
Status (automatic)
No particular signs of unrest in the last 24 hours — 2 earthquakes recorded, within the system's normal range.🕰️ Last eruption / event — ~159 years ago
Mánáreyjar eruption 1867–68 (~1867). The Tjörnes Fracture Zone produces Iceland's largest earthquakes — M7+ historically. The last major was Kópasker 1976.
The Tjörnes Fracture Zone off North Iceland — a transform plate boundary, not a volcano in the usual sense. Frequent and sometimes large earthquakes occur here (e.g. 1755 and the 1976 Kópasker quake). (overview — more at vedur.is) · circle on the map = rough outline of the system (radius).
📜 Did you know?
The Tjörnes Fracture Zone connects the North Atlantic ridge to the Reykjanes ridge and produces Iceland's largest earthquakes — historically M7+. The last major was the Kópasker earthquake of 1976 (M6.5).
Historical eruptions in the system — points colored by size, blue circle shows where we are now in time.
❓ What if a major Tjörnes earthquake occurs?
TFZ produces Iceland's largest earthquakes — historically M7+. The last major was Kópasker 1976 (M6.5). Most likely scenarios: M6+ on the Grímsey or Húsavík-Flatey fault. Tsunami risk in Eyjafjörður and Skagafjörður (historically 1872, 4 m surge). Impact: Damage to buildings in Húsavík, Raufarhöfn, Grímsey. Roads may be cut. Coastal flooding possible. Sources: 1976 Kópasker (M6.5), 1872 Húsavík (M7), Met Office hazard assessment.
This is not a forecast. Based on historical experience and official hazard assessments from the Met Office / Civil Protection.
Points = earthquake locations in the selected window, coloured by magnitude: ● M3+ · ● M2+ · ● smaller (a sample if more than 800).
Earthquakes
2
Largest
M0.3
M3,0+
0
Depth range
5–8 km
Earthquakes over time
Cumulative count · 2 earthquakes · total moment ≈ M0.4 · count moment
Depth (0 km at top). Grey: fixed depth.
Not enough depth data.
Magnitude distribution
Earthquakes
3
Largest
M0.9
M3,0+
0
Depth range
5–8 km
Earthquakes over time
Cumulative count · 3 earthquakes · total moment ≈ M1.0 · 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
46
Largest
M2.0
M3,0+
0
Depth range
0–15 km
Earthquakes over time
Cumulative count · 46 earthquakes · total moment ≈ M2.4 · count moment
No significant hypocenter migration — activity is stationary (R²=0.07, n=46); no sign of a propagating dike. Migration shows automatically if R²≥0.30.
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
223
Largest
M2.4
M3,0+
0
Depth range
0–22 km
Earthquakes over time
Cumulative count · 223 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
2408
Largest
M2.8
M3,0+
0
Depth range
0–23 km
Earthquakes over time
Cumulative count · 2408 earthquakes · total moment ≈ M3.6 · count moment
Depth (0 km at top) — shallowing in the data (8.1→6.0 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 ≈ 1.29 ± 0.10 (i.e. likely 1.20–1.39, 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
6562
Largest
M4.7
M3,0+
9
Depth range
0–24 km
Earthquakes over time
Cumulative count · 6562 earthquakes · total moment ≈ M4.7 · 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=341)
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 and varies only due to moderate local weathe…
IMO tremor plot (station gri). Most of the signal is weather and surf — not eruption confirmation. All stations: vedur.is.
Weather now: wind 6 m/s (Flatey á Skjálfanda), waves 0.7 m — moderate.
Baseline volcanic tremor is currently normal and varies only due to moderate local weather and ocean waves. (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 | Area |
|---|---|---|---|
| 2026-06-10 07:04 | M0.3 | 5.2 | Tjörnes / N-land |
| 2026-06-10 07:04 | M0.2 | 7.9 | Tjörnes / N-land |
| 2026-06-09 06:20 | M0.9 | 5.2 | Tjörnes / N-land |
| 2026-06-07 13:14 | M0.6 | 9.4 | Tjörnes / N-land |
| 2026-06-07 03:02 | M1.1 | 5.2 | Tjörnes / N-land |
| 2026-06-07 02:56 | M1.2 | 5.2 | Tjörnes / N-land |
| 2026-06-07 01:14 | M1.4 | 9.1 | Tjörnes / N-land |
| 2026-06-07 01:14 | M1.1 | 10.3 | Tjörnes / N-land |
| 2026-06-06 16:35 | M0.3 | 11.8 | Tjörnes / N-land |
| 2026-06-06 12:49 | M1.3 | 8.9 | Tjörnes / N-land |
| 2026-06-06 11:51 | M0.1 | 11.8 | Tjörnes / N-land |
| 2026-06-06 11:51 | M0.6 | 5.3 | Tjörnes / N-land |
| 2026-06-06 08:58 | M0.4 | 10.1 | Tjörnes / N-land |
| 2026-06-06 03:35 | M1.5 | 1.1 | Tjörnes / N-land |
| 2026-06-06 03:35 | M1.6 | 7.6 | Tjörnes / N-land |
| 2026-06-06 00:55 | M0.8 | 1.1 | Tjörnes / N-land |
| 2026-06-06 00:38 | M0.8 | 10.1 | Tjörnes / N-land |
| 2026-06-06 00:38 | M1.1 | 1.1 | Tjörnes / N-land |
| 2026-06-06 00:33 | M0.9 | 10.9 | Tjörnes / N-land |
| 2026-06-06 00:33 | M0.8 | 14.2 | Tjörnes / N-land |
| 2026-06-06 00:11 | M1.2 | 15.4 | Tjörnes / N-land |
| 2026-06-06 00:11 | M1.2 | 8.7 | Tjörnes / N-land |
| 2026-06-05 20:21 | M0.8 | 12.1 | Tjörnes / N-land |
| 2026-06-05 18:46 | M0.5 | 7.7 | Tjörnes / N-land |
| 2026-06-05 18:29 | M2.0 | 11.0 | Tjörnes / N-land |
| 2026-06-05 18:08 | M1.4 | 10.2 | Tjörnes / N-land |
| 2026-06-05 18:08 | M1.7 | 13.3 | Tjörnes / N-land |
| 2026-06-05 17:07 | M1.0 | 5.3 | Tjörnes / N-land |
| 2026-06-05 13:09 | M0.5 | 13.3 | Önnur svæði |
| 2026-06-05 12:23 | M1.1 | 13.6 | Tjörnes / N-land |
| 2026-06-05 12:23 | M1.1 | 0.0 | Tjörnes / N-land |
| 2026-06-05 12:02 | M0.7 | 6.8 | Tjörnes / N-land |
| 2026-06-05 12:02 | M0.9 | 8.6 | Tjörnes / N-land |
| 2026-06-05 11:04 | M1.2 | 14.2 | Tjörnes / N-land |
| 2026-06-05 11:04 | M1.2 | 0.0 | Tjörnes / N-land |
| 2026-06-04 16:06 | M1.3 | 5.2 | Tjörnes / N-land |
| 2026-06-04 16:06 | M1.5 | 6.0 | Tjörnes / N-land |
| 2026-06-04 16:06 | M1.4 | 15.2 | Tjörnes / N-land |
| 2026-06-04 15:47 | M1.0 | 1.1 | Tjörnes / N-land |
| 2026-06-04 05:35 | M1.7 | 9.5 | Tjörnes / N-land |
| 2026-06-04 05:35 | M1.8 | 4.8 | Önnur svæði |
| 2026-06-03 17:24 | M0.9 | 11.5 | Tjörnes / N-land |
| 2026-06-03 17:23 | M0.4 | 0.0 | Tjörnes / N-land |
| 2026-06-03 17:23 | M0.7 | 5.6 | Tjörnes / N-land |
| 2026-06-03 15:08 | M0.5 | 11.3 | Tjörnes / N-land |
| 2026-06-03 09:53 | M0.9 | 8.1 | Tjörnes / N-land |
| 2026-06-03 08:10 | M0.0 | 5.2 | Tjörnes / N-land |
| 2026-06-03 07:55 | M0.5 | 5.2 | Tjörnes / N-land |
| 2026-06-03 07:23 | M0.3 | 20.1 | Tjörnes / N-land |
| 2026-06-03 06:35 | M-0.0 | 0.8 | Tjörnes / N-land |
| 2026-06-03 06:19 | M1.0 | 5.5 | Tjörnes / N-land |
| 2026-06-03 06:12 | M0.6 | 5.2 | Tjörnes / N-land |
| 2026-06-03 06:11 | M0.9 | 9.6 | Tjörnes / N-land |
| 2026-06-03 05:57 | M0.9 | 5.2 | Tjörnes / N-land |
| 2026-06-02 18:41 | M0.2 | 10.5 | Tjörnes / N-land |
| 2026-06-02 17:45 | M0.2 | 10.7 | Tjörnes / N-land |
| 2026-06-02 17:37 | M0.7 | 5.0 | Tjörnes / N-land |
| 2026-06-02 11:03 | M-0.1 | 0.0 | Tjörnes / N-land |
| 2026-06-01 23:05 | M1.1 | 5.7 | Tjörnes / N-land |
| 2026-06-01 22:56 | M1.0 | 5.8 | Tjörnes / N-land |
For the advanced — expert charts — Coulomb, migration, InSAR
🔬 Coulomb stress transfer — advanced analysis
9 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.
System journal
Automatic snapshots and media coverage, in chronological order. Subscribe: RSS · ntfy
skjalftar-tjornes-grimsey2026-06-06 03:50:06 UTC
In the last 24 hours, 21 earthquakes were recorded in the Tjörnes Fracture Zone, a transform plate boundary rather than a volcano, with activity increasing but remaining within normal levels for this area. The increase is characterized by distributed background seismicity rather than swarms and most closely resembles the period around March 8, 2026. The largest earthquake was M2.0 with a cumulative magnitude of Mw 2.4, and results are automatic preliminary results. Further details on trends and maps can be found lower on the page.2026-06-01 23:20:15 UTC
In the last 24 hours, 14 earthquakes were recorded in the Tjörnes Fracture Zone, a transform plate boundary rather than a conventional volcano, with activity now increasing compared to the weekly average. This increase is considered unusual for the area and is characterized by distributed background seismicity rather than distinct swarms, with the largest event at M2.3 and a cumulative magnitude of Mw 2.6. The activity most closely resembles the period around February 19, 2026; these figures are automatic preliminary results, and further details are available below.2026-06-01 19:15:10 UTC
In the last 24 hours, 15 earthquakes were recorded in the Tjörnes Fracture Zone, a plate boundary rather than a conventional volcano, with activity increasing but remaining within normal levels for this area. The increase is primarily due to distributed background seismicity rather than distinct swarms, with the largest earthquake in the past 48 hours being M2.3 and a cumulative magnitude of Mw 2.6. These automatic preliminary results resemble the period around May 5, 2025, and further details on trends 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).
Data: Icelandic Met Office (Skjálftalísa API), automatic preliminary results — may change. This is not an official warning. Official warnings: vedur.is and Civil Protection (112).