Early-est:     Off East Coast of Honshu, Japan    2026.10.01-17:17:17.18    q:B      mb:5.1*    Mwp:-    Mwpd:-    Td*T50Ex:0.4     fmamp_polarity:./hypo.1790875036944.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1790875036944.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1790875036944.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* [52]    Mwp: 5.4X [2]    Mwpd: 5.5Xinv [3]
Region: Off East Coast of Honshu, Japan
Origin Time: 2026.10.01-17:17:17.18 UTC
Hypocenter: lat: 39.88°  lon: 143.25°  [+/-19km]    depth: 9km  [+/-15km]
Location Quality: qualityCode:  B     stdErr: 1.7s   assocPhases: 78   usedPhases: 62
minDist: 1.9°   maxDist: 87.1°   AzGap: 182°   2ndAzGap: 187°   atten: -0.97 [+/-0.15]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 9km   maxHorUnc: 19km   azMaxHorUnc: 119°
68%ConfEllipsoid:   semiMajorAxisLength: 24km   majorAxisAzimuth: 120°   majorAxisPlunge: 14°   semiIntermediateAxisLength: 14km   intermediateAxisAzimuth: 241°   intermediateAxisPlunge: 63°   semiMinorAxisLength: 10km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [41]    Td: 1.1s [6]    Td*T50Ex: 0.4 [6]    To: 16.2s [40]
Closest plate boundaries:
   Pacific \ Okhotsk [subduction zone]: distance: ~80km
   Okhotsk / Pacific [subduction zone]: distance: ~150km
Subduction geometry:    Zone: Kamchatka/Kurils/Japan: DEBUG: error: [Errno 2] No such file or directory: 'gmt'    Slab depth at epicenter: error: evaluating slab depth: -999.9
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 YES (80km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   0.4
   0.4
   0.4
Td*To:
     17.8
     17.8
     17.8
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.1790875036944.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 136°   dip: 17°   rake: -6°
Nodal Plane 2: strike: 231°   dip: 88°   rake: -107°
Quality: azimuthalGap: -1°   stationPolarityCount: 48   misfitWeightCount: 7.2   misfit: 0.25   stationDistributionRatio: 0.29   meanDistP: 54.9   meanDistT: 51.8   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1790875036944.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.1790875036944.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (No solution available)
Nodal Plane 1: strike: 999°   dip: 99°   rake: 999°
Nodal Plane 2: strike: 324°   dip: 13°   rake: 135°
Quality: azimuthalGap: 182°   stationPolarityCount: 46   misfit: 0.99   stationDistributionRatio: 0.00   rmsAngDiffAccPref: 0.00   fracAcc30degPref: 0.00   qualityCode: E
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1790875036944.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1790875036944
Event info last updated: 2026.10.01-18:16:00 UTC
Event first association/location: 2026.10.01-17:22:00 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA