M 5.5 in Tonga on 20 May 2018 00:42 UTC

Hazard models

EQ parameters
Shakemap
Tsunami

Event summary

This earthquake is expected to have a low humanitarian impact based on the magnitude and the affected population and their vulnerability.

Earthquake Magnitude: 5.5M
Depth: 10 Km
Lat/Lon: -21.0205 , -173.8412
Event Date: 20 May 2018 00:42 UTC
19 May 2018 12:42 Local
Exposed Population: Few people within 100km
Source: NEIC us1000e8t0
Inserted at: 20 May 2018 01:23 UTC
INFORM Coping capacity of the alert score: 1.1 (Tonga)

GDACS Score

For more info on GDACS alert score click here.
  Earthquake
(Shakemap)		 GDACS score
NEIC 0 0
us1000e8t0 Scaled population (vector) 0  
  C1 shakemap -0.59  
  C2 shakemap 0.53  
  Country Vulnerability 0  
  INFORM_normalised 1  
Maximum expected impact using different data sources.

ShakeMap is a product of the USGS Earthquake Hazards Program in conjunction with the regional seismic networks. ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes.


Episode Timeline

IDAlertScoreDateMag, DepthMMI*Population**Tsunami risk***Delay (hh:mm)Source
1211241 0 20 May 2018 00:42 5.5M, 10km 3.27 N/A (in MMI>=VII) 00:22 NEIC
1211242 0 20 May 2018 00:42 5.5M, 10km 3.27 N/A (in MMI>=VII) 00:40 NEIC
The episode that generated the alert; the next major evaluations beyond 12 hours will not trigger additional alerts.
The episode that has the last updated information.
* The max MMI detected for sources having shakemaps;
** The population detected in MMI>=7 for episode with shakemap or in a 100km radius;
*** The tsunami max height.

Exposed population

The earthquake happened in Tonga ,of Tonga (population 6,614) . The alertlevel for this event is GREEN

Intensity Population
no people
1000 people


Shakemaps Timeline

AlertShake id #ScoreepisodeidLat/LonMagnitudeDepthMax MMIDate shake (UTC)Delay (hh:mm) 
1 0 1211241 -20.975/-174.001 5.5 10 3.27 20 May 2018 01:08 00:26 (new episode)
2 0 1211242 -20.975/-174.001 5.5 10 3.27 20 May 2018 01:23 00:41 (new episode)
3 0 1211242 -21.02/-173.841 5.5 10 3.27 20 May 2018 01:25 00:43 (upd of #2)
4 0 1211242 -21.02/-173.841 5.5 10 3.27 20 May 2018 02:46 02:04 (upd of #3)

Affected Provinces

Intensity Region Province Country Population
Tonga Tonga 37000 people

Affected populated places. Areas of interest

Intensity Name Region Province Country City class Population Distance
Ohonua Tonga Village 1200 people 120 km
Niutoua Tonga Village - 126 km
Kolonga Tonga Village - 130 km
Fatumu Tonga Village - 134 km
Mua Tonga Village - 134 km
Fuaamotu Tonga Village - 138 km
Nuku'alofa Tonga Capital 24000 people 143 km
Pangai Tonga Village 1700 people 144 km
Pea Tonga Village - 146 km
Nukunuku Tonga Village - 152 km
Houma Tonga Village - 152 km
Foui Tonga Village - 156 km

see full list


Critical infrastructure

Airports, ports, nuclear plants and hydrodams at risk, if affected, are listed below.

Airports

Intensity Name IATA Code Elevation (m) Usage Runway type IFR Runway Length (ft) Distance
Eua Kaufana EUA unknown 0 122 km
Fua'amotu International TBU 38 Civ. Paved Yes 8700 137 km
Haapai HPA 12 Civ. Unpaved Yes 3900 147 km

Ports

Intensity Name LOCODE Country Distance
Eua Island Tonga 117 km
Nuku'alofa TOTBU Tonga 142 km
Pangai TOPAN Tonga 145 km

More information

For a full list of available products related to this event, please refer to the GDACS Resources page.