Tjörnes Fracture Zone
Zone — systems within: Tjörnes / Grímsey · Eyjafjarðaráll · Kolbeinseyjarhryggur
Points = earthquake locations in the selected window, coloured by magnitude: ● M3+ · ● M2+ · ● smaller (a sample if more than 800).
Earthquakes
4
Largest
M0.8
M3,0+
0
Depth range
5–12 km
Earthquakes over time
Cumulative count · 4 earthquakes · total moment ≈ M0.9 · 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
8
Largest
M1.7
M3,0+
0
Depth range
5–12 km
Earthquakes over time
Cumulative count · 8 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.
Earthquakes
57
Largest
M2.3
M3,0+
0
Depth range
0–15 km
Earthquakes over time
Cumulative count · 57 earthquakes · total moment ≈ M2.6 · count moment
No significant hypocenter migration — activity is stationary (R²=0.00, n=57); 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
269
Largest
M2.4
M3,0+
0
Depth range
0–22 km
Earthquakes over time
Cumulative count · 269 earthquakes · total moment ≈ M3.0 · 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
2729
Largest
M3.2
M3,0+
3
Depth range
0–24 km
Earthquakes over time
Cumulative count · 2729 earthquakes · total moment ≈ M3.8 · count moment
Depth (0 km at top) — shallowing in the data (8.2→6.1 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 ≈ 1.22 ± 0.08 (i.e. likely 1.14–1.31, M≥1.7, n=157)
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
7369
Largest
M4.7
M3,0+
15
Depth range
0–24 km
Earthquakes over time
Cumulative count · 7369 earthquakes · total moment ≈ M4.8 · 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.
Gutenberg-Richter b ≈ 1.11 ± 0.05 (i.e. likely 1.06–1.16, M≥1.7, n=455)
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.
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).