Early-est:     Taiwan Region    2026.09.28-18:20:49.99    q:C      mb:4.7*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1790619650134.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1790619650134.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1790619650134.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* [14]    Mwp: 4.3X [2]    Mwpd: - [0]
Region: Taiwan Region
Origin Time: 2026.09.28-18:20:49.99 UTC
Hypocenter: lat: 23.79°  lon: 122.10°  [+/-22km]    depth: 59km  [+/-36km]
Location Quality: qualityCode:  C     stdErr: 1.7s   assocPhases: 35   usedPhases: 20
minDist: 1.1°   maxDist: 167.8°   AzGap: 82°   2ndAzGap: 98°   atten: -0.90 [+/-0.40]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 18km   maxHorUnc: 22km   azMaxHorUnc: 149°
68%ConfEllipsoid:   semiMajorAxisLength: 39km   majorAxisAzimuth: 94°   majorAxisPlunge: 64°   semiIntermediateAxisLength: 27km   intermediateAxisAzimuth: 346°   intermediateAxisPlunge: 9°   semiMinorAxisLength: 17km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.4 [6]    Td: 1.4Xs [1]    Td*T50Ex: - [0]    To: 6.7s [5]
Closest plate boundaries:
   Okinawa - Philippine Sea [oceanic transform fault]: distance: ~20km
   Philippine Sea - Yangtze [continental transform fault]: distance: ~110km
   Yangtze - Okinawa [continental rift boundary]: distance: ~110km
Subduction geometry: none or not available
Decision table (TEST!):
Event type: Subduction Zone Other Thrust/Normal Strike-slip
Compatible close plate boundary?:
 no
 no
 YES (20km)
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       59km
       59km
       59km
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.1790619650134.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 168°   dip: 25°   rake: -140°
Nodal Plane 2: strike: 41°   dip: 74°   rake: -70°
Quality: azimuthalGap: -1°   stationPolarityCount: 18   misfitWeightCount: 8.8   misfit: 0.08   stationDistributionRatio: 0.48   meanDistP: 39.8   meanDistT: 41.6   qualityCode: C
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1790619650134.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.1790619650134.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (Warning: Unreliable solution, qualityCode=C)
Nodal Plane 1: strike: 202°   dip: 14°   rake: -114°
Nodal Plane 2: strike: 47°   dip: 78°   rake: -84°
Quality: azimuthalGap: 114°   stationPolarityCount: 18   misfit: 0.23   stationDistributionRatio: 0.67   rmsAngDiffAccPref: 36.19   fracAcc30degPref: 0.55   qualityCode: C
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1790619650134.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1790619650134
Event info last updated: 2026.09.28-19:19:01 UTC
Event first association/location: 2026.09.28-18:35:18 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA