参考答案：错

解析：[听力原文] Our discussion of earthquakes would be incomplete if we didn’t raise the possibility of their being caused by external forces. As you know there are increases and decreases in episodes of seismic activity, but there is no regular or predictable pattern.

[分析]： 特定信息的找寻和理解。 本题要求理解seismic activity(地震活动)。根据相关原文可知As you know there are increases and decreases in episodes of seismic activity，but there is no regular or predictable pattern，即地震活动周期有起有伏，没有规律可言，也无法预测其态势。而题干认为地震活动周期越来越复杂，可能会引起地球的颤动，显然与原文不符，因此是错误的。[解题关键] 识别听力材料中的关键信息，并对其上下文充分理解，是解答本题的关键。如本题中的关键信息是seismic activity，如果对有关该词部分的内容充分理解，便能作出正确的判断。