Early-est:     Volcano Islands, Japan Region    2026.08.15-19:32:25.33    q:A      mb:5.3*    Mwp:5.5    Mwpd:-    Td*T50Ex:0.6     fmamp_polarity:./hypo.1786822355099.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1786822355099.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1786822355099.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: 5.3* [96]    Mwp: 5.5 [9]    Mwpd: 5.6Xinv [10]
Region: Volcano Islands, Japan Region
Origin Time: 2026.08.15-19:32:25.33 UTC
Hypocenter: lat: 23.44°  lon: 143.15°  [+/-7km]    depth: 5km  [+/-12km]
Location Quality: qualityCode:  A     stdErr: 1.6s   assocPhases: 157   usedPhases: 124
minDist: 10.1°   maxDist: 161.2°   AzGap: 27°   2ndAzGap: 48°   atten: -0.94 [+/-0.16]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 7km   maxHorUnc: 7km   azMaxHorUnc: 33°
68%ConfEllipsoid:   semiMajorAxisLength: 12km   majorAxisAzimuth: 159°   majorAxisPlunge: 72°   semiIntermediateAxisLength: 9km   intermediateAxisAzimuth: 47°   intermediateAxisPlunge: 7°   semiMinorAxisLength: 8km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [76]    Td: 1.6s [18]    Td*T50Ex: 0.6 [18]    To: 2.5s [72]
Closest plate boundaries:
   Philippine Sea - Mariana [oceanic transform fault]: distance: ~40km
   Mariana / Pacific [subduction zone]: distance: ~100km
   Philippine Sea / Pacific [subduction zone]: distance: ~110km
Subduction geometry:    Zone: Izu-Bonin: 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 (100km)
 no
 YES (40km)
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   0.6
   0.6
   0.6
Td*To:
     4.0
     4.0
     4.0
Mwp magnitude:
       5.5
       5.5
       5.5
Hypocenter depth:
       5km
       5km
       5km
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.1786822355099.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 51°   dip: 63°   rake: 22°
Nodal Plane 2: strike: 311°   dip: 71°   rake: 151°
Quality: azimuthalGap: -1°   stationPolarityCount: 97   misfitWeightCount: 12.6   misfit: 0.18   stationDistributionRatio: 0.46   meanDistP: 47.3   meanDistT: 42.0   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1786822355099.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.1786822355099.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 302°   dip: 58°   rake: 166°
Nodal Plane 2: strike: 39°   dip: 78°   rake: 32°
Quality: azimuthalGap: 81°   stationPolarityCount: 97   misfit: 0.25   stationDistributionRatio: 0.67   rmsAngDiffAccPref: 32.82   fracAcc30degPref: 0.73   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1786822355099.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1786822355099
Event info last updated: 2026.08.15-20:31:01 UTC
Event first association/location: 2026.08.15-19:36:02 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA