When the superpower of its time the British Empire founded their colonies in North America they realised that these colonies will one day become a Superpower. Unknown to them at the time is that the North American continent is arguably the most dynamic continent on earth and that rapid periods of destruction and renew occur here on a regular interval.
Historically after a big earthquake in Mexico with in a year there is a large earthquake in Alaska, followed by a large earthquake on the San Andreas Fault which is followed by a large earthquake on the Cascadian Fault line. Depending on where on the Cascadian Fault the earthquake takes place a massive tsunami wave could destroy several coastal structures and some areas may even drop into the ocean.
A large Mexico earthquake and large Alaska earthquake have already occurred so if history should repeat itself as it often do Los Angeles and Cascadia could have the big one before the end of 2018.
This is only one of several changes North America will have in the future, the New Madrid Fault produces a large earthquake every 200years, the last one was 200years ago. A part of the Canary Islands drops into the ocean every now and then, creating a Tsunami that can destroy several coastal building on the US west coast. The volcano on the Canary Islands which are responsible for these brake offs are starting to awake.
Talking about volcanoes, there is Yellowstone, a super volcano that can trigger an ice age if it should blow. This volcano will erupt one day and when it does a third of the USA will be destroyed.
Talking about ice age, one day we will enter a new ice age, unlike the mini ice age we are entering now, a ice age can bury the north eastern states in the USA under one mile of ice.
North America is on a timer, and destruction and renew will come.