There is no need to worry. This dream has no reference to external life, such as a natural; disaster. It is symbolic of an inner mental state. It seems very dramatic and so it might appear scary. But after many years of dream work I do not find it scary.
The sun almost always represent the ego, meaning your sense of self, the center of your conscious identity. Just as the sun is the center of our universe, so the sun of your being, your consciousness, is the center of your world, your experience of life. The sun being black could mean that you are hiding yourself; that you feel that no one knows the real you that is hidden inside; that you are numbing your feelings; that you have dark, negative feelings about yourself. There are various possibilities. Maybe it's a feeling of someone else eclipsing you, grabbing the attention and making you feel like nothing (blacked out).
The red molten lava has been in the news lately with many image from the Hawaiian volcano--did you see those pictures or videos? That was a very striking image, which would make an impression on everyone's mind. And then in a dream the mind chooses that image to symbolize erupting emotions. Red hot emotions are of course angry feelings. A force builds up inside you, like a volcano, and finally you feel you might not be able to hold it in anymore--it could overflow in a burst of emotion that maybe you were trying to restrain or push down. I think it would help if you reflect and try to see if you know who you are angry at. Most likely it is a parent or family member. The person may be making you feel bad about yourself, and that rightly makes you upset and angry. Once you become more consciously aware of the feelings behind the dream, you will get relief from the anxiety caused by the dream. The dream does not come to hurt you; it comes to make you more conscious.