Given all of the possibilities you may decided you cannot prepare for them all so why bother. Some may have this attitude and other may focus on a particular event they believe is most likely. The events can be anything from a 10.0 earthquake to a comet strike that tilts the earth’s axis. Anything can happen but what you have to think about is what is most likely to happen.
For those interested in prepping but have not yet begun should understand that many of the items needed to survive a major earthquake are also needed to survive hurricanes, floods and so on. There are of course specific materials and equipment needed to survive a nuclear or chemical attack but in the beginning you should begin with the non-disaster specific items. Suits that protect you against radiation, chemicals and biological agents are extremely expensive and hard to obtain. You would have to find a reputable hazardous material (Hazmat) handling company that specializes in chemical spills, biological and nuclear waste cleanup.
There are other options. Four feet of soil will protect you from airborne contaminates so if economics and other factors are a consideration look into turning your basement into a protective zone. You have to look at all possibilities because doing nothing is not an option.
You will always need a shelter, water, fire and food so concentrate on these essentials first because without these, those other protective measures, such as radiation suits and lead lined bunkers will not mean much.
You have to prepare using common sense and not buy into all of the hype out there. Some may have you believe that you need to prepare for a government takeover. News flash the government is already here. Stockpiling to fight an invading army is not productive. If an army wanted what you have, they would come in and take it, no amount of weaponry or booby traps will stop them. Frankly, when something does happen, no one, especially the government will know you even exist. It will be up to you to survive with or without government intervention.
You cannot fight an army so save some time and money and do the common sense preparations that you need. There may be an economic collapse, which means the dollar is no good. This is a real threat, and you must have the means to survive in the new normal. Food, water and medications will be the new currency. You will need items to barter with such as tobacco products, alcohol and knowledge.
Study after study has shown that drugs, alcohol and tobacco products are the items that looters take off the shelves first during a crisis. Some law enforcement records show that food products were still on grocery store shelves days after a disaster struck, while other non-food items were gone in matter of hours after a crisis. You can see the priorities of some people. People will steal electronics during an extended power outage and have no way to use those items. They will move food products out of the way to get to certain other items. Drugs stores will be looted for certain medications, while vials of insulin and blood pressure medication are moved aside.
The looters do not have the ability to think long-term they are living in the moment and will be the first to die of dehydration and starvation. You must begin to think long-term and forget about the three days of supplies all the experts recommend in the days leading up to a disaster. You need to think about surviving for months and possibly years.