Early-est:     Off East Coast of Honshu, Japan    2026.02.10-18:52:01.45    q:B      mb:5.1*    Mwp:-    Mwpd:-    Td*T50Ex:0.5     fmamp_polarity:./hypo.1770749522369.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1770749522369.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1770749522369.mech.hash.thumb.jpg

Automatic solution - this event has not been reviewed by a seismologist
Automatically determined event information may be incorrect!

Earthquake Details:
Magnitude: mb: 5.1* [53]    Mwp: 4.8X [2]    Mwpd: 4.9Xinv [1]
Region: Off East Coast of Honshu, Japan
Origin Time: 2026.02.10-18:52:01.45 UTC
Hypocenter: lat: 35.53°  lon: 143.88°  [+/-27km]    depth: 9km  [+/-16km]
Location Quality: qualityCode:  B     stdErr: 1.6s   assocPhases: 82   usedPhases: 58
minDist: 4.1°   maxDist: 150.2°   AzGap: 70°   2ndAzGap: 104°   atten: -1.14 [+/-0.16]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 16km   maxHorUnc: 27km   azMaxHorUnc: 144°
68%ConfEllipsoid:   semiMajorAxisLength: 34km   majorAxisAzimuth: 323°   majorAxisPlunge: 7°   semiIntermediateAxisLength: 21km   intermediateAxisAzimuth: 230°   intermediateAxisPlunge: 20°   semiMinorAxisLength: 15km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [44]    Td: 0.9s [7]    Td*T50Ex: 0.5 [7]    To: 7.3s [43]
Closest plate boundaries:
   Pacific \ Okhotsk [subduction zone]: distance: ~120km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (120km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   0.5
   0.5
   0.5
Td*To:
     6.6
     6.6
     6.6
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       9km
       9km
       9km
Slab depth at epicenter:
       n/a
       -
       -
Tsunami and Rupture predictions (TEST!): No prediction: Event too small (Mwp<7.0) or too few Mwp readings (N<20)
./hypo.1770749522369.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 32°   dip: 24°   rake: -1°
Nodal Plane 2: strike: 123°   dip: 90°   rake: -114°
Quality: azimuthalGap: -1°   stationPolarityCount: 53   misfitWeightCount: 9.3   misfit: 0.22   stationDistributionRatio: 0.48   meanDistP: 39.0   meanDistT: 47.2   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1770749522369.mech.fmamp_polarity.mechanism.jpg
First-motion Focal Mechanism (FMAMP_POLARITY_WAVEFORM):    (No solution available)
Nodal Plane 1: strike: 0°   dip: 0°   rake: 0°
Nodal Plane 2: strike: 270°   dip: 90°   rake: 90°
Quality: azimuthalGap: -1°   stationPolarityCount: 0   misfitWeightCount: -1.0   misfit: -1.00   stationDistributionRatio: -1.00   meanDistP: -1.0   meanDistT: -1.0   qualityCode: X
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity_waveform
./hypo.1770749522369.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 7°   dip: 27°   rake: 46°
Nodal Plane 2: strike: 235°   dip: 71°   rake: 109°
Quality: azimuthalGap: 103°   stationPolarityCount: 52   misfit: 0.29   stationDistributionRatio: 0.67   rmsAngDiffAccPref: 31.44   fracAcc30degPref: 0.63   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1770749522369.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1770749522369
Event info last updated: 2026.02.10-19:51:00 UTC
Event first association/location: 2026.02.10-18:59:03 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA