My own interpretation sums up the difference as scope and proximity. Risk awareness often involves a larger scope or reach while Situational awareness is usually close to you and affecting your immediate survival.
Risk awareness is very broad and applicable to all sorts of circumstances and positions. It is often used in business as a means to ensure good practices of risk mitigation. In terms of survival preparedness, risk awareness should encompass your normal way of thinking and way of life; an outer layer of awareness which will signal you to adapt appropriate measures to reduce the potential effects of risk. The risks themselves, in this context, are more hypothetical while grounded in levels of probability. The risk scenarios have typically not occurred yet and the adaptation scenarios are planned and put in place based on their probability of occurrence and impact.
Situational awareness is your personal awareness of your immediate surroundings and the risks presented there, right now. Although we can prepare for circumstances which may result from situational awareness scenarios, the act itself of situational awareness is happening in your immediate time and space at your physical vicinity. It may be all clear, or it may be dangerous, but you would not know it if you were not consciously aware of the situation around you.
Survival preparedness is largely an adaptation to both risk and situational awareness. An example of adaptation to risk awareness may be as large as establishing a one year food supply or as little as adding a first aid kit to your car’s 72-hour kit. Adaptation to situational awareness may be as extreme as firing on an aggressor intent on killing you or as mild as crossing the street to avoid walking towards an oncoming gang of thugs.
Both types of awareness have an extremely important role in survival preparedness. In fact, they must come first in your thought process. You need to know what you are preparing for, so that you can proceed with the appropriate actions and risk mitigation. It’s logical. You do not want to use a ‘shotgun’ approach to preparedness, but instead approach it as a ‘sniper’. Target your specific goals based on the threats themselves.