Tjörnes / Grímsey

Seismicity by period · derived statistics from Skjálftalísa (Icelandic Met Office)

Status (automatic)

No particular signs of unrest in the last 24 hours — 13 earthquakes recorded, within the system's normal range.

🕰️ Last eruption / event — ~160 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.

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.

Glossary & magnitude scale →

🌊 Volcanic tremor — The volcanic tremor baseline is currently elevated compared to recent days. (AI)

IMO tremor plot (station gri). Most of the signal is weather and surf — not eruption confirmation. All stations: vedur.is ↗.

Weather now: wind 11 m/s (Flatey á Skjálfanda), waves 2.3 m — notable — likely weather.

The volcanic tremor baseline is currently elevated compared to recent days. (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
2026-09-11 13:58	M0.4	0.0	Tjörnes / N-land
2026-09-11 08:56	M1.3	9.6	Tjörnes / N-land
2026-09-11 08:04	M0.7	10.0	Tjörnes / N-land
2026-09-11 07:38	M1.5	1.5	Tjörnes / N-land
2026-09-11 06:57	M0.2	0.0	Tjörnes / N-land
2026-09-11 06:52	M1.0	0.5	Tjörnes / N-land
2026-09-11 06:18	M1.3	11.2	Tjörnes / N-land
2026-09-11 06:15	M2.7	13.0	Tjörnes / N-land
2026-09-11 06:12	M1.3	11.3	Tjörnes / N-land
2026-09-11 06:11	M1.2	0.9	Tjörnes / N-land
2026-09-11 04:13	M-0.3	9.2	Tjörnes / N-land
2026-09-11 04:04	M0.0	0.0	Tjörnes / N-land
2026-09-11 03:52	M0.5	18.9	Tjörnes / N-land
2026-09-10 16:58	M0.9	8.9	Tjörnes / N-land
2026-09-10 16:47	M-0.4	0.0	Tjörnes / N-land
2026-09-10 12:50	M0.4	8.9	Tjörnes / N-land
2026-09-10 11:38	M-0.4	0.0	Tjörnes / N-land
2026-09-10 01:10	M0.0	2.1	Tjörnes / N-land
2026-09-09 22:08	M0.7	3.6	Tjörnes / N-land
2026-09-09 21:55	M1.0	14.6	Tjörnes / N-land
2026-09-09 19:26	M0.2	27.7	Tjörnes / N-land
2026-09-09 17:33	M0.1	19.4	Tjörnes / N-land
2026-09-09 08:46	M1.7	17.3	Other areas
2026-09-09 03:48	M1.1	7.2	Tjörnes / N-land
2026-09-09 00:31	M0.9	10.2	Other areas
2026-09-08 16:42	M1.2	9.5	Tjörnes / N-land
2026-09-08 10:02	M0.3	0.0	Tjörnes / N-land
2026-09-08 06:34	M0.9	16.1	Tjörnes / N-land
2026-09-08 01:43	M-0.2	12.7	Tjörnes / N-land
2026-09-07 23:39	M0.3	10.4	Tjörnes / N-land
2026-09-06 18:54	M-0.1	18.1	Tjörnes / N-land
2026-09-06 04:02	M1.6	9.9	Tjörnes / N-land
2026-09-06 00:43	M-0.1	0.5	Tjörnes / N-land
2026-09-06 00:16	M0.9	18.5	Tjörnes / N-land
2026-09-06 00:06	M0.6	6.2	Tjörnes / N-land
2026-09-06 00:05	M0.4	19.3	Tjörnes / N-land
2026-09-05 21:51	M0.0	0.0	Tjörnes / N-land
2026-09-05 15:07	M0.5	5.0	Tjörnes / N-land
2026-09-05 14:59	M0.7	0.0	Tjörnes / N-land
2026-09-05 10:17	M0.3	0.0	Tjörnes / N-land
2026-09-05 09:26	M0.8	9.7	Tjörnes / N-land
2026-09-05 05:10	M-0.4	0.0	Tjörnes / N-land
2026-09-04 18:30	M0.5	3.8	Tjörnes / N-land
2026-09-04 16:54	M0.9	0.0	Tjörnes / N-land
2026-09-03 21:28	M1.0	10.5	Tjörnes / N-land
2026-09-03 12:01	M0.8	12.2	Tjörnes / N-land
2026-09-02 12:57	M1.1	13.6	Tjörnes / N-land
2026-09-02 12:05	M0.8	13.3	Tjörnes / N-land
2026-09-02 07:17	M0.8	10.3	Tjörnes / N-land
2026-09-02 04:30	M0.8	10.2	Tjörnes / N-land
2026-09-02 01:48	M0.5	12.3	Tjörnes / N-land
2026-09-01 16:10	M0.0	10.3	Tjörnes / N-land
2026-09-01 12:18	M1.0	9.7	Tjörnes / N-land
2026-09-01 10:04	M0.9	12.4	Tjörnes / N-land
2026-09-01 02:25	M0.7	14.0	Tjörnes / N-land
2026-09-01 02:18	M0.9	10.0	Tjörnes / N-land
2026-09-01 02:07	M1.4	5.1	Tjörnes / N-land
2026-08-31 20:04	M0.9	9.1	Tjörnes / N-land
2026-08-31 16:42	M1.2	13.4	Tjörnes / N-land
2026-08-31 15:54	M0.9	10.0	Tjörnes / N-land

For the advanced — expert charts — Coulomb, migration, InSAR

🔬 Coulomb stress transfer — advanced analysis

7 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.

System journal

Automatic snapshots and media coverage, in chronological order. Subscribe: RSS · ntfy skjalftar-tjornes-grimsey

2026-08-26 13:20:17 UTC

In the last 24 hours, 21 earthquakes were recorded in the Tjörnes Fracture Zone, representing an increase from the weekly average but remaining normal activity for this area. The activity is characterized by distributed background seismicity rather than swarms and most closely resembles the period around May 1, 2026. The largest earthquake was M1.9 and the cumulative magnitude over the past 48 hours is Mw 2.3. Results are automatic preliminary results and further details can be found below on the page.

2026-08-05 15:15:06 UTC

Over the last 24 hours, seismic activity in the Tjörnes Fracture Zone off the north coast of Iceland has been increasing and is currently measured somewhat higher than usual for this area. A total of 23 earthquakes were detected during the last 24 hours, which is well above the weekly average, with the largest event over the last two days measuring magnitude 1.7 and the cumulative magnitude for that period reaching 2.1. This increase is characterized by scattered background activity rather than short-lived swarms, as approximately 75% of events over the last seven days were independent and only 25% were related to swarms or aftershocks. The current activity most closely resembles the period around August 4, 2025, although it should be noted that these are automatic preliminary results where depth is unreliable.

2026-08-04 20:25:05 UTC

Over the last 24 hours, 24 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, where frequent earthquakes are common. This activity is increasing compared to the average of the past week and month, but it is still considered within normal limits for this area and is characterized by scattered background activity rather than swarms, with 77% of events over the last seven days being independent. The largest earthquake in the last 48 hours was magnitude 1.6 and the cumulative moment magnitude in the area was Mw 2.1, although these results are automatic preliminary data with unreliable depths. The current activity most closely resembles the period around August 4, 2025 as a historical analogue, and further details and maps of the development can be found below on this page.

2026-08-04 09:20:06 UTC

Over the last 24 hours, activity has been increasing on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, and is known for frequent earthquakes. There were 24 earthquakes detected in the last 24 hours, which is well above the weekly average and represents slightly more activity than usual for this area, with the largest earthquake in the last 48 hours measuring magnitude 1.6 and the cumulative moment magnitude measuring 2.1 Mw. This increase is characterized by scattered background activity rather than swarms, as 85% of the events over the last seven days were independent and only 15% were related to swarms or aftershocks. These are automatic preliminary results where depth is unreliable, and the current activity most closely resembles the period around August 4, 2025, as a historical analogue. Maps and further details on this development are available below.

2026-08-04 06:15:04 UTC

Over the last 24 hours, 23 earthquakes were detected in the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform plate boundary rather than a volcano in the conventional sense, where frequent and sometimes large earthquakes occur. This activity is increasing compared to the average of the last week and month which was 11 earthquakes per day, but it is still considered within what is normal for this area. The activity consists of scattered background activity rather than swarms, as 84% of the events over the last seven days were independent, with the largest earthquake in the last 48 hours measuring magnitude 1.6 and the cumulative moment magnitude amounting to 2.1 Mw. This development most closely resembles the period around 4 August 2025, but it should be noted that these are automatic preliminary results where depth is unreliable. Maps and further data on the development can be found lower on this page.

2026-08-03 23:10:05 UTC

Over the past 24 hours, 15 earthquakes were detected in the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a typical volcano, known for frequent and sometimes large earthquakes. This seismic activity is within the normal range for this area and remains similar to the past week, characterized by scattered background activity rather than swarms, with 83% of events over the last seven days classified as independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), and the cumulative moment magnitude for the same period was 3.1 (Mw 3.1), noting that these are automatic preliminary results where depth is unreliable. The current activity most closely resembles the period around August 4, 2025 as a historical analogue, and further details and maps can be found lower on the page.

2026-08-03 19:00:06 UTC

Over the last 24 hours, 14 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, a transform plate boundary rather than a conventional volcano where frequent earthquakes are common. This activity is similar to the past week and is considered entirely normal for this area, with measurements indicating scattered background activity rather than earthquake swarms. The largest earthquake in the last 48 hours was magnitude (Mw) 3.1, with the cumulative moment magnitude of the period also at Mw 3.1. These are automatic preliminary results where depth is unreliable, and the current activity most closely resembles the period around August 4, 2025.

2026-08-03 16:50:04 UTC

Over the last 24 hours, 15 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, where frequent earthquakes are common. This seismic activity is within the normal range for this area and remains similar to the past week, characterized by scattered background activity rather than swarms, with 83% of events over the last seven days being independent. The largest earthquake in the last 48 hours was magnitude 3.1 (with a cumulative moment magnitude of Mw 3.1), though these results are automatic preliminary data where depth is unreliable. The current activity most closely resembles the period around August 4, 2025 as a historical analogue, and further details and maps can be found below on this page.

2026-08-03 13:15:05 UTC

Over the past 24 hours, 10 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary and not a volcano in the ordinary sense, where frequent earthquakes are common. This activity is similar to the past week and is considered entirely normal for this area, with measurements showing scattered background activity rather than swarms, as 86% of events over the last seven days were independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), and the cumulative moment magnitude in the area was Mw 3.1 during the same period. The current activity most closely resembles the period around August 4, 2025, but it must be noted that these are automatic preliminary results where depth is unreliable.

2026-08-03 10:25:04 UTC

Over the last 24 hours, 9 earthquakes were detected on the Tjörnes fracture zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a volcano in the conventional sense where frequent earthquakes are common. The activity is similar to the past week and is considered within the normal range for this area, characterized by scattered background activity rather than swarms as 85% of the events over the last seven days were independent. The largest earthquake in the last 48 hours was magnitude 3.1 (combined magnitude Mw 3.1), and these results are automatic preliminary findings where depth is unreliable. This activity most closely resembles the period around August 4, 2025, and further maps and trend analyses can be found below.

2026-08-03 05:05:04 UTC

Over the last 24 hours, 10 earthquakes were detected in the Tjörnes fracture zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, and is known for frequent earthquake activity. This seismic activity is similar to that of the past week and is considered completely normal for this area, consisting mostly of scattered background activity rather than swarms, with 85% of events over the last seven days classified as independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), with the cumulative moment magnitude of the period also measuring 3.1 (Mw 3.1). The current activity most closely resembles the period around August 3, 2025 as a historical analogue, though it must be noted that all results are automatic preliminary findings where depth is unreliable.

2026-08-03 02:45:06 UTC

Over the last 24 hours, 13 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a plate boundary rather than a typical volcano and is known for frequent seismic activity. This activity is currently increasing compared to the weekly average of 8 earthquakes per day, though it remains within what is considered normal for this area. The activity consists of diffuse background seismicity rather than swarms, with 85% of events over the last seven days classified as independent background earthquakes, closely resembling the period around August 3, 2025. The largest earthquake in the last 48 hours was magnitude 3.1 (with a cumulative moment magnitude of Mw 3.1), but please note that these are automatic preliminary results and their depth is unreliable. Maps and further data on this development are available below.

2026-08-03 00:10:06 UTC

Over the last 24 hours, 12 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a typical volcano, where frequent earthquakes are common. This seismic activity is within the normal range for this area and remains similar to the past week, with measurements indicating scattered background activity rather than swarms, as 85% of the events over the last seven days were independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), with a cumulative moment magnitude of Mw 3.1, though these are automatic preliminary results where depth is unreliable. The current activity most closely resembles the period around August 3, 2025, as a historical comparison and is not a prediction for the future.

2026-08-02 22:05:06 UTC

Over the last 24 hours, 11 earthquakes were detected in the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, and is characterized by frequent seismic activity. This activity is similar to that of the past week and remains within normal limits for this area, manifesting as scattered background activity rather than swarms, with 85% of the events over the last seven days classified as independent. The largest earthquake in the last 48 hours was magnitude 3.1 (Mw), with the cumulative seismic moment also at 3.1, though these are automatic preliminary results where depth estimates are unreliable. The current activity most closely resembles the period around August 3, 2025 as a historical analogue, and further details along with maps can be found below.

2026-08-02 18:50:05 UTC

Over the past 24 hours, 10 earthquakes have been detected in the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, where frequent earthquakes are common. This seismic activity is within the normal range for this area and remains similar to the past week, consisting of scattered background activity rather than swarms, with 84% of events over the last seven days classified as independent. The largest earthquake in the last 48 hours was magnitude (Mw) 3.1, with the cumulative moment magnitude also at Mw 3.1, though these are unverified automatic preliminary results with unreliable depth estimates. The current activity most closely resembles the period around August 3, 2025, when 40 earthquakes were recorded, and further details and maps of the area can be found lower on this page.

2026-08-02 13:25:05 UTC

Over the last 24 hours, 9 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a plate boundary and not a volcano in the ordinary sense, where frequent earthquakes are common. This activity is similar to the past week and is considered entirely normal for this area, consisting mostly of scattered background activity (84% independent events) rather than swarms. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), with the cumulative moment magnitude for the period also at 3.1 (Mw 3.1). The current activity most closely resembles the period around August 3, 2025, though it should be noted that these are automatic preliminary results and depths are unreliable. Maps and further details on the development are available below.

2026-08-02 09:30:06 UTC

Over the last 24 hours, 5 earthquakes were detected on the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano where frequent earthquakes are common. This activity is similar to the past week and is considered normal for this area, with measurements showing scattered background activity rather than swarms, as 83% of the events over the last 7 days were independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1), and the cumulative moment magnitude for the period was also 3.1 (Mw 3.1). This activity most closely resembles the period around August 3, 2025, when 40 earthquakes were recorded, although it must be noted that these are automatic preliminary results where depth is unreliable. Maps and further data on this development can be found lower on the page.

2026-08-02 05:05:05 UTC

Over the last 24 hours, 8 earthquakes were detected in the Tjörnes Fracture Zone off the north coast of Iceland, which is a transform fault zone on a plate boundary rather than a conventional volcano, where frequent earthquakes are common. This activity is similar to the past week and is considered entirely normal for this area, with measurements showing scattered background activity rather than swarms, as 85% of events over the last seven days were independent. The largest earthquake in the last 48 hours was magnitude 3.1 (M3.1) and the cumulative moment magnitude in the area was Mw 3.1, though these are automatic preliminary results where depth is unreliable. The current activity most closely resembles the period around August 3, 2025, when 40 earthquakes were recorded, and further details and maps of the area can be found below.

2026-07-21 18:45:03 UTC

Over the last 24 hours, 24 earthquakes were detected on the Tjörnes fracture zone off the north coast of Iceland, which is a plate boundary rather than a conventional volcano and is known for frequent earthquakes. This activity is increasing and is somewhat higher than usual for this area, consisting mostly of diffuse background activity (68% independent events) rather than swarms. The largest earthquake in the last 48 hours was magnitude 1.8 and the cumulative moment magnitude was 2.3 Mw, although these are automatic preliminary results where depth is unreliable. The current activity most closely resembles the period around 31 March 2026, and further details and development charts can be found below.

2026-06-06 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.

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).

Tjörnes / Grímsey

Earthquakes over time

Cumulative count and moment

Magnitude distribution

Earthquakes over time

Cumulative count and moment

Magnitude distribution

Earthquakes over time

Cumulative count and moment

Magnitude distribution

Earthquakes over time

Cumulative count and moment

Magnitude distribution

Earthquakes in the system

System journal