Early-est:     Southeast of Honshu, Japan    2026.03.31-15:38:46.89    q:C      mb:4.5*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:     fmamp_polarity_waveform:     hash:

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

Earthquake Details: Magnitude: mb: 4.5* [12]    Mwp: - [0]    Mwpd: - [0] Region: Southeast of Honshu, Japan Origin Time: 2026.03.31-15:38:46.89 UTC Hypocenter: lat: 34.00°  lon: 140.38°  [+/-16km]    depth: 102km  [+/-33km] Location Quality: qualityCode:  C     stdErr: 1.3s   assocPhases: 35   usedPhases: 18 minDist: 1.0°   maxDist: 65.8°   AzGap: 162°   2ndAzGap: 211°   atten: -0.47 [+/-0.38] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 16km   azMaxHorUnc: 89° 68%ConfEllipsoid:   semiMajorAxisLength: 33km   majorAxisAzimuth: 161°   majorAxisPlunge: 81°   semiIntermediateAxisLength: 20km   intermediateAxisAzimuth: 267°   intermediateAxisPlunge: 2°   semiMinorAxisLength: 15km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.5X [2]    Td: -s [0]    Td*T50Ex: - [0]    To: 4.0Xs [2] Closest plate boundaries:    Okhotsk - Philippine Sea [oceanic convergent boundary]: distance: ~70km    Philippine Sea / Pacific [subduction zone]: distance: ~140km    Pacific \ Okhotsk [subduction zone]: distance: ~140km    Amur / Philippine Sea [subduction zone]: distance: ~180km 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 (140km)  YES (70km)  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        102km        102km        102km 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)

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 275°   dip: 24°   rake: 174° Nodal Plane 2: strike: 10°   dip: 88°   rake: 66° Quality: azimuthalGap: -1°   stationPolarityCount: 16   misfitWeightCount: 4.2   misfit: 0.05   stationDistributionRatio: 0.44   meanDistP: 53.9   meanDistT: 49.4   qualityCode: D Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
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
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C) Nodal Plane 1: strike: 303°   dip: 29°   rake: -154° Nodal Plane 2: strike: 190°   dip: 78°   rake: -64° Quality: azimuthalGap: 103°   stationPolarityCount: 16   misfit: 0.20   stationDistributionRatio: 0.75   rmsAngDiffAccPref: 28.62   fracAcc30degPref: 0.70   qualityCode: C Method: methodID: smi:gov.usgs/focalmec/HASH_1.2

Event ID: smi:alomax.net_BETA/author/ee/event/1774971526900
Event info last updated: 2026.03.31-16:37:00 UTC
Event first association/location: 2026.03.31-15:42:00 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA