The 2105 Surprise earthquake and tsunami were events that took place off the North Sea Coast of the UK on January 29, 2105, with no warnings before the event actually happened. At 0448 UTC, a 15 mile stretch of the sea bed was thrown upwards by a magnitude 6.9 earthquake, causing a 10 meter tsunami to sweep across the North Sea form the origin of the rupture zone.
The cause of the earthquake is believed to be a previously undiscovered thrust fault on the bed of the North Sea, which was reawakened by drilling near the 100 million year fault, increasing the pressure as the water got into it, causing the whole 15 mile length to rupture and crack, exposing it again. The earthquake was calculated to have been at a depth of 8 km below sea level, and the British Geological Survey claims that shaking near the epicenter could have lasted between 3 and 4 minutes, as the pressure from the fault being drilled into was released.
The first tsunami hit the English North Sea Coast 20 minutes after the earthquake, taking both local residents and the BGS by total surprise, and as a result, 9643 people died, an dover 20,000 were injured by the resulting tsunami. In addition, more than 35,000 people were left homeless by the combined effects of the earthquake and tsunami, due to the lack of earthquake proofing, due to the lack of powerful earthquakes in the UK, causing them to collapse during the violent tremors. Taller, high-rise buildings were toppled, before sinking into the ground as the underlying clays and soils liquefied in the tremors from the earthquake, which was caused by months of wet weather in the UK.
The BGS later reported that shaking intensities peaked between 8 and 9 on the Mercalli Scale in the worst hit areas, making this one of the highest observed since records began in 1930.
In the aftermath of the earthquake and tsunami, the British Red Cross began handing out disaster relief supplies and funds in the affected areas, and also drained the grounds of flooding and excess water form the appalling weather and the tsunami wave.
Over the next 25 years, a massive effort was made to earthquake proof any buildings in the effected areas, in order to prevent such a disaster from happening again. The clean up, repairs and rebuilding project was completed at a cost of $755 billion, making it the costliest response to a natural disaster on record.
4 aftershocks, measuring 6.2, 5.7, 5.0 and 4.6 occurred on January 19, February 4, February 8 and February 19, respectively. A study done into the newly surfaced fault uncovered a distinct history of faulting in the area, with magnitude 4-5 earthquakes happening every 10-15 years, and magnitude 6+ earthquakes happening every 100-250 years, each causing tsunamis in the process