很多堰塞湖是在地震发生后，产生泥石流，堵塞河流而形成的。

Many barrier lakes formed after the earthquake caused landslides, which blocked rivers.

youdao

公元4 ~7世纪间，古城上游河段曾先后两次发生河岸滑坡堵塞河水，形成堰塞湖，导致孔雀河改道，从而彻底断绝了维系楼兰古城生命的唯一水源，古城不得不被废弃而且无法复兴。

In the 4 ~ 7 century, the water resources from Kongqiu river was cut off because of old Kongqiu river changed channel resulted from landslip on upper reaches. The old city had to discard.

youdao

公元4 ~7世纪间，古城上游河段曾先后两次发生河岸滑坡堵塞河水，形成堰塞湖，导致孔雀河改道，从而彻底断绝了维系楼兰古城生命的唯一水源，古城不得不被废弃而且无法复兴。

In the 4 ~ 7 century, the water resources from Kongqiu river was cut off because of old Kongqiu river changed channel resulted from landslip on upper reaches. The old city had to discard.

youdao