Early-est:     Tonga Islands    2026.04.03-02:50:23.90    q:B      mb:4.6*    Mwp:-    Mwpd:-    Td*T50Ex:-     fmamp_polarity:./hypo.1775184623931.mech.fmamp_polarity.thumb.jpg     fmamp_polarity_waveform:./hypo.1775184623931.mech.fmamp_polarity_waveform.thumb.jpg     hash:./hypo.1775184623931.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: 4.6* [13]    Mwp: - [0]    Mwpd: - [0]
Region: Tonga Islands
Origin Time: 2026.04.03-02:50:23.90 UTC
Hypocenter: lat: -17.39°  lon: -174.51°  [+/-16km]    depth: 196km  [+/-20km]
Location Quality: qualityCode:  B     stdErr: 2.2s   assocPhases: 46   usedPhases: 38
minDist: 4.4°   maxDist: 152.3°   AzGap: 74°   2ndAzGap: 147°   atten: -2.61 [+/-0.41]
Location Uncertainty: 68%ConfEllipse:   minHorUnc: 13km   maxHorUnc: 16km   azMaxHorUnc: 10°
68%ConfEllipsoid:   semiMajorAxisLength: 24km   majorAxisAzimuth: 21°   majorAxisPlunge: 46°   semiIntermediateAxisLength: 17km   intermediateAxisAzimuth: 141°   intermediateAxisPlunge: 27°   semiMinorAxisLength: 15km
Tsunamigeneic Assesment:
Discriminants: Prob Underwater: >99%
T50Ex: 0.5 [7]    Td: -s [0]    Td*T50Ex: - [0]    To: 2.9s [7]
Closest plate boundaries:
   Tonga - Niuafo'ou [continental rift boundary]: distance: ~10km
Subduction geometry:    Zone: Kermadec-Tonga: 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?:
 no
 no
 no
Prob underwater:
 >99%
 >99%
 >99%
Td*T50Ex:
   -
   -
   -
Td*To:
     -
     -
     -
Mwp magnitude:
       -
       -
       -
Hypocenter depth:
       196km
       196km
       196km
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.1775184623931.map.jpg

First-motion Focal Mechanism (FMAMP_POLARITY):    (Warning: VERY UNRELIABLE SOLUTION, qualityCode=D)
Nodal Plane 1: strike: 146°   dip: 22°   rake: -143°
Nodal Plane 2: strike: 21°   dip: 77°   rake: -72°
Quality: azimuthalGap: -1°   stationPolarityCount: 15   misfitWeightCount: 2.5   misfit: 0.07   stationDistributionRatio: 0.37   meanDistP: 52.1   meanDistT: 55.5   qualityCode: D
Method: methodID: smi:net.alomax/focalmec/fmamp_0.0.5X_2016.06.14/_polarity
./hypo.1775184623931.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.1775184623931.mech.fmamp_polarity_waveform.mechanism.jpg
First-motion Focal Mechanism (HASH):    (No solution available)
Nodal Plane 1: strike: 999°   dip: 99°   rake: 999°
Nodal Plane 2: strike: 324°   dip: 13°   rake: 135°
Quality: azimuthalGap: 178°   stationPolarityCount: 15   misfit: 0.99   stationDistributionRatio: 0.77   rmsAngDiffAccPref: 35.62   fracAcc30degPref: 0.00   qualityCode: E
Method: methodID: smi:gov.usgs/focalmec/HASH_1.2
./hypo.1775184623931.mech.hash.mechanism.jpg

Event ID: smi:alomax.net_BETA/author/ee/event/1775184623931
Event info last updated: 2026.04.03-03:49:01 UTC
Event first association/location: 2026.04.03-03:11:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA