Taipei, July 6 (CNA) A warning system developed to monitor volcanic activity in northern Taiwan and guide disaster prevention measures will be launched by the end of this year, the Central Weather Bureau (CWB) said Monday.

The system will target the Datun volcano system in Taipei and Turtle Island in Yilan, which are active volcanoes, defined as a volcano that has erupted at least once in the past 10,000 years.

It will also provide guidance that enables the two administrative areas, along with New Taipei and Keelung, to draft related measures, the bureau said.

Volcanic activity will be identified as grade 0, 1, and 2, which will be represented by green, yellow and red lights, respectively, the bureau said.

A green light means a volcano is displaying normal activity, while a yellow light means there are signs there could be an eruption, according to the bureau's Seismology Center.

A red light means the volcano could erupt soon or has already erupted, it said.

Monitoring criteria include changes in the shape of the Earth's crust, the release of certain gases, and changes in underwater temperature, the bureau said, adding that both it and the Ministry of Technology and Science have observation stations on Datun Mountain.

Although volcanoes in Taiwan have been inactive for thousands of years, an Academia Sinica study found that they could still erupt.

Warnings will be delivered via the Internet, text messages and cell broadcasts, a geo-targeted messaging service that notifies people in certain areas, according to the CWB.