Early-est:     Near East Coast of Honshu, Japan    2026.03.27-15:24:44.30    q:C      mb:4.9*    Mwp:-    Mwpd:-    Td*T50Ex:0.7     fmamp_polarity:./hypo.1774625089338.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1774625089338.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1774625089338.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: 4.9* [36]    Mwp: 4.5X [3]    Mwpd: 5.1Xinv [2]
Region: Near East Coast of Honshu, Japan
Origin Time: 2026.03.27-15:24:44.30 UTC
Hypocenter: lat: 39.45°  lon: 142.27°  [+/-51km]    depth: 52km  [+/-37km]
Location Quality: qualityCode:  C     stdErr: 1.5s   assocPhases: 60   usedPhases: 40
minDist: 1.6°   maxDist: 151.0°   AzGap: 99°   2ndAzGap: 124°   atten: -0.97 [+/-0.21]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 15km   maxHorUnc: 51km   azMaxHorUnc: 95°
68%ConfEllipsoid:   semiMajorAxisLength: 65km   majorAxisAzimuth: 275°   majorAxisPlunge: 18°   semiIntermediateAxisLength: 33km   intermediateAxisAzimuth: 122°   intermediateAxisPlunge: 70°   semiMinorAxisLength: 19km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [24]    Td: 1.5s [4]    Td*T50Ex: 0.7 [4]    To: 29.6s [19]
Closest plate boundaries:
   Pacific \ Okhotsk [subduction zone]: distance: ~170km
   Okhotsk / Pacific [subduction zone]: distance: ~240km
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 (170km)
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   0.7
   0.7
   0.7
Td*To:
     44.4
     44.4
     44.4
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       52km
       52km
       52km
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.1774625089338.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 34°   dip: 25°   rake: -49°
Nodal Plane 2: strike: 170°   dip: 72°   rake: -107°
Quality: azimuthalGap: -1°   stationPolarityCount: 38   misfitWeightCount: 7.7   misfit: 0.07   stationDistributionRatio: 0.59   meanDistP: 34.1   meanDistT: 35.0   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1774625089338.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.1774625089338.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):
Nodal Plane 1: strike: 14°   dip: 27°   rake: -82°
Nodal Plane 2: strike: 185°   dip: 63°   rake: -94°
Quality: azimuthalGap: 91°   stationPolarityCount: 38   misfit: 0.19   stationDistributionRatio: 0.67   rmsAngDiffAccPref: 21.95   fracAcc30degPref: 0.91   qualityCode: B
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1774625089338.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1774625089338
Event info last updated: 2026.03.27-16:23:00 UTC
Event first association/location: 2026.03.27-15:32:00 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA