UPDATED 9 August 2006

AMSTERDAM — An earthquake shook the north of the Netherlands early on Tuesday morning. Measuring 3.5 on the Richter Scale, it was equal in strength to the strongest earthquake on record in the northern Netherlands. This took place in Alkmaar five years ago.

Tuesday's quake in Groningen at around 7am was registered by all seismic stations in the country. It was centred on the town of Middelstum which lies in the middle of the gas fields in the province.

The town has experienced several earthquake in recent years. Weather and seismic agency KNMI and local broadcaster RTV Noord were bombarded with telephone calls and emails from concerned residents after the latest quake.

Hein Haak said the earthquake was the largest ever measured in Groningen and was felt across the entire province.

There have been 10 quakes roughly equivalent to this magnitude since the first earthquake caused by the gas drilling took place in 1986. There have been several dozen smaller shooks during this period too.

The earthquakes result from tension in the earth's crust caused by the extraction of gas. The tension increases in correlation to the amount of gas extraction. The first earthquake took place 27 years after drilling began in Groningen in 1959.

The last big quake in Groningen occurred in 2003 when the province experienced three within a month.

NAM, the company responsible for the gas extraction in the north of the Netherlands, said shortly after the earthquake that it had not received any damages claims.

This changed by Tuesday evening. A spokesperson said at least 20 calls had come in during the course of the day but it was not clear how many would lead to official claims. "People are ringing about damage varying from tears in plasterwork to cracked windows."

NAM expects to receive more calls. "Naturally there are people currently on holiday who may ring us when they get home," the spokesperson said.

Local residents who can prove their property has been damaged by an earthquake caused by the gas operation can claim from NAM. An independent expert decides whether the firm has to make financial restitution.

[Copyright Expatica News + ANP 2006]

Subject: Dutch news