The Geohazard Service Unit (GSU) is responsible for monitoring Earthquakes, Tsunami and Volcanic Activities occurring around the Kingdom and vicinity between 13.00°S – 23.00°S latitudes and 172.00°W – 178.00°W longitudes.

1. Vision/Objectives

The Geohazard Services Unit’s main objective is to monitor, investigate and mitigate impacts of Geo-Hazard Activities.

2. Background

Tonga Seismic Network

In 2002, Tonga was fortunate to collaborate with the Japanese Government through JICA to establish Tonga’s Seismic Network. This network consists of 5 seismic stations in Tongatapu, Vava’u, Ha’apai and the two Niuas to monitor seismic activities in Tonga and around the region. All equipment for the Tonga Seismic Network was purchased from and set up by Nanometrics which is a leading provider in advanced monitoring solutions and equipment for studying man-made and natural seismicity. They are a global leader in services, instrumentation and accessories that encompass all the necessary components for the development and operation of seismic networks. In 2008 the Tonga Seismic Network had its first upgrade. This involved upgrading the Seismic Shed and the seismic equipment.

3. Key Roles and Responsibilities

  • Provide information to public on Earthquakes, Tsunami and Volcanoes.
  • Provide information to Engineers for construction.
  • Monitor Seismic Activities and Provide information for Tsunami Early Warning.
  • Conduct Hazard Research and Assessments.
  • Public Awareness

4. Laws and Act

There are currently no legislations under this Section.

5. Activities

Monitoring of Seismic Activities

Earthquakes are being analyzed locally using the Tonga Hydra Automatic Analyzer. It allows us to determine the details of an earthquake event within 5-10 minutes of the event occurrence. This can also be done manually when automation fails through the Tonga-Fiji Manal Seismic Analyzer.

Other sources such as the USGS and CISN are used to gather information regarding an earthquake. Both provide real time data and a visual alert system of earthquake occurring around the World.

For more information, please click on this LINK

Monitoring of Volcanic Activities

Volcanic activity is monitored remotely using satellite images via internet. GSU focuses on Volcanic Ash Cloud Monitoring, Pumice Raft Tracking and involvement in Scientific Research to Volcanic Islands.

For more information, please click on this LINK

Implementation of Pacific Resilience Program.

GSU is involved in the implementation of the World Bank funded Project called Pacific Resilience Program (PREP). The Pacific Resilience Program will strengthen disaster early warning and preparedness, and mainstream disaster risk and climate change into development planning and financing. Component 1 of PREP focuses on early warning and disaster preparedness and aims to strengthen the ability of Tonga to make warning information actionable by those at risk.

Through this Project the Geohazard Unit intends to upgrade the Tonga Seismic Network to improve monitoring of earthquakes and strengthen early warning of Tsunami with the Tonga Meteorological Services (TMS).

6. Hazard Facts


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