People in Groningen - a densely populated area in the northern Netherlands - live directly above Europe’s biggest natural gas field. They’ve got used to the odd rumble or two, but this year alone 20 earthquakes have shaken the region. Now The Dutch Oil Company (NAM) has announced it wants to increase its rate of gas extraction. Thus far, the quakes have been relatively low in magnitude, but scientists warn this is likely to change. Angry homeowners, complaining of cracked walls and roofs, are demanding the plans be reconsidered.