Early-est:     Tonga Islands    2026.03.28-08:51:17.28    q:C      mb:4.2*    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: 4.2* [10]    Mwp: - [0]    Mwpd: - [0] Region: Tonga Islands Origin Time: 2026.03.28-08:51:17.28 UTC Hypocenter: lat: -18.15°  lon: -174.92°  [+/-46km]    depth: 246km  [+/-36km] Location Quality: qualityCode:  C     stdErr: 1.9s   assocPhases: 30   usedPhases: 15 minDist: 4.8°   maxDist: 150.3°   AzGap: 98°   2ndAzGap: 164°   atten: -1.21 [+/-0.50] Location Uncertainty: 68%ConfEllipse:   minHorUnc: 25km   maxHorUnc: 46km   azMaxHorUnc: 51° 68%ConfEllipsoid:   semiMajorAxisLength: 58km   majorAxisAzimuth: 231°   majorAxisPlunge: 9°   semiIntermediateAxisLength: 36km   intermediateAxisAzimuth: 119°   intermediateAxisPlunge: 67°   semiMinorAxisLength: 30km Tsunamigeneic Assesment: Discriminants: Prob Underwater: >99% T50Ex: 0.0 [6]    Td: -s [0]    Td*T50Ex: - [0]    To: 1.3s [6] Closest plate boundaries:    Tonga - Niuafo'ou [continental rift boundary]: distance: ~20km    Niuafo'ou - Australia [oceanic spreading ridge]: distance: ~140km    Tonga - Australia [oceanic spreading ridge]: distance: ~180km    Tonga / Pacific [subduction zone]: distance: ~240km 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?:  YES (240km)  no  no Prob underwater:  >99%  >99%  >99% Td*T50Ex:    -    -    - Td*To:      -      -      - Mwp magnitude:        -        -        - Hypocenter depth:        246km        246km        246km 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: 232°   dip: 17°   rake: -43° Nodal Plane 2: strike: 4°   dip: 79°   rake: -102° Quality: azimuthalGap: -1°   stationPolarityCount: 13   misfitWeightCount: 3.9   misfit: 0.08   stationDistributionRatio: 0.49   meanDistP: 51.9   meanDistT: 50.1   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: VERY UNRELIABLE SOLUTION, qualityCode=D) Nodal Plane 1: strike: 158°   dip: 52°   rake: 149° Nodal Plane 2: strike: 268°   dip: 66°   rake: 42° Quality: azimuthalGap: 149°   stationPolarityCount: 13   misfit: 0.27   stationDistributionRatio: 0.45   rmsAngDiffAccPref: 39.49   fracAcc30degPref: 0.58   qualityCode: D Method: methodID: smi:gov.usgs/focalmec/HASH_1.2

Event ID: smi:alomax.net_BETA/author/ee/event/1774687880277
Event info last updated: 2026.03.28-09:50:00 UTC
Event first association/location: 2026.03.28-08:59:01 UTC
Software: Early-est 1.2.10 (2024.02.23)
Agency: alomax.net_BETA