Early-est:     Near S. Coast of Western Honshu    2026.08.17-07:36:19.66    q:B      mb:4.7*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1786952179941.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1786952179941.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1786952179941.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: 4.7* [43]    Mwp: 4.4X [1]    Mwpd: - [0]
Region: Near S. Coast of Western Honshu
Origin Time: 2026.08.17-07:36:19.66 UTC
Hypocenter: lat: 34.70°  lon: 135.61°  [+/-40km]    depth: 371km  [+/-33km]
Location Quality: qualityCode:  B     stdErr: 1.8s   assocPhases: 74   usedPhases: 57
minDist: 1.3°   maxDist: 156.3°   AzGap: 40°   2ndAzGap: 69°   atten: -0.87 [+/-0.22]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 30km   maxHorUnc: 40km   azMaxHorUnc: 91°
68%ConfEllipsoid:   semiMajorAxisLength: 49km   majorAxisAzimuth: 271°   majorAxisPlunge: 9°   semiIntermediateAxisLength: 38km   intermediateAxisAzimuth: 180°   intermediateAxisPlunge: 8°   semiMinorAxisLength: 32km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: <1%
T50Ex: 0.0 [24]    Td: 0.4Xs [2]    Td*T50Ex: - [0]    To: 1.3s [23]
Closest plate boundaries:
   Amur / Philippine Sea [subduction zone]: distance: ~220km
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 (220km)
 no
 no
Prob underwater:
 <1%
 <1%
 <1%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       371km
       371km
       371km
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.1786952179941.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):
Nodal Plane 1: strike: 118°   dip: 15°   rake: -155°
Nodal Plane 2: strike: 4°   dip: 84°   rake: -77°
Quality: azimuthalGap: -1°   stationPolarityCount: 48   misfitWeightCount: 14.6   misfit: 0.12   stationDistributionRatio: 0.69   meanDistP: 26.9   meanDistT: 28.1   qualityCode: B
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1786952179941.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.1786952179941.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):
Nodal Plane 1: strike: 100°   dip: 18°   rake: -167°
Nodal Plane 2: strike: 357°   dip: 86°   rake: -72°
Quality: azimuthalGap: 58°   stationPolarityCount: 48   misfit: 0.23   stationDistributionRatio: 0.73   rmsAngDiffAccPref: 18.99   fracAcc30degPref: 0.94   qualityCode: B
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1786952179941.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1786952179941
Event info last updated: 2026.08.17-08:35:00 UTC
Event first association/location: 2026.08.17-07:46:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA