What is the future • Because of the very long return period getting people to act according to key risk? messaging will always be hard – ie; many members of the public will not respond well to an actual tsunami. • The risk of a tsunami occurring will remain the same regardless of any human action. • There continues to be a desire to build and live on the Coast and this trend shows no sign of diminishing. Earthquake Overview In the South Island, the Marlborough Fault System is a series of major parallel faults which pass close to Blenheim; the Wairau Fault 1.6km to the north, Vernon Fault 8kms to the south and the Awatere Fault 14 kms to the south. These have characteristic magnitudes of 7.1 to 7.6. The parallel faults join together further south to form the Alpine Fault which carries most of the total plate boundary strain. This is a very distinct feature along most of its length because of the Southern Alps that have been uplifted along its eastern side, making it clearly visible from space. It is considered to be at high risk of producing a major earthquake in the next 50 years. Other principal active faults in the District include the Clarence, Kekerengu, Elliot, Jordon and Hope faults. All of these faults are capable of producing large magnitude earthquakes and collectively these faults have an average return period of between 28 and 51 years (Robertson and Smith 2004). Figure 5: Ten Years of Shallow Earthquakes in New Zealand Marlborough Civil Defence Emergency Management Plan, 2017-2022 Page 88