Tremorsense (Ex): A creature with tremorsense is sensitive to vibrations in the ground and can automatically pinpoint the location of anything that is in contact with the ground. Aquatic creatures with tremorsense can also sense the location of creatures moving through water. The ability’s range is specified in the creature’s descriptive text.
If no straight path exists through the ground from the creature to those that it's sensing, then the range defines the maximum distance of the shortest indirect path. It must itself be in contact with the ground, and the creatures must be moving.
As long as the other creatures are taking physical actions, including casting spells with somatic components, they're considered moving; they don't have to move from place to place for a creature with tremorsense to detect them.
TREMORSENSE
A creature that has tremorsense is sensitive to vibrations in the ground and can automatically pinpoint the location of anything that is in contact with the ground within range and is not totally still. A creature that has tremorsense must also be in contact with the ground, and the creatures it’s trying to sense must be taking physical actions, including casting spells with somatic components. Creatures don’t have to move from place to place for a creature that has tremorsense to detect them.
If no direct path exists through the ground from the creature that has tremorsense to those it’s sensing, then the ability’s range defi nes the maximum distance of the shortest indirect path. Aquatic creatures that have tremorsense can also sense the location of creatures moving through water, as long as the creature that has tremorsense is in contact with the same water.
紫色——MM；红色——SRD；蓝色——RC
总之我建议看原文~
