What does this symbol indicate on a weather map?

Which plate boundary causes plates to collide forming mountain ranges, volcanoes, and island arcs? give an example of this type of plate boundary. 2. at which plate boundary do rifts and mid-oceans ridges form? give an example of this type of plate boundary. 3. at which plate boundary do plates slide past each other while moving in opposite directions? give an example of this type of boundary.