This phenomenon occurs when the effect of strong volcanic activities begin to weaken and the equatorialtrough fills up and retreats southwards.
这种现象发生在强火山活动影响开始减弱，赤道槽南移填塞以后。
2
The depths of the trough and the deeper peaks are almost coincident with those of the south boundaries of the South Equatorial Current and the Equatorial Undercurrent, respectively.