4. Layered Strata Formed in Three Hours. On June 12, 1980 a third explosive eruption produced 8m of stratification that amazed geologists. Successive layers are traditionally thought to require long periods of time to form; yet upwards of 100 layers accumulated mostly between the nighttime hours of 9 and 12. While a plume swiftly ascended nine miles above the mountain, wave after wave of pyroclastic flows began hurtling out of the crater and down the north slope, each dusting the valley below with another lamination.
4. Kufanyika kwa Tabaka la Mawe kwa Masaa Matatu. Mnamo Juni 12,1980 m’bubujiko wa tatu wenye kishindo ulifanya mita 8 ya tabaka la mawe lililo washangaza wana jiolojia.Mfuatano wa safu kiasili unadhaniwa kuhitaji muda mrefu kufanyika;ilhali zaidi ya safu 100 ililimbikizwa hasa masaa ya usiku kati ya saa 9 na saa 12.Wakati nyoya liliinuka maili tisa juu ya mlima wa katikati na chini ya mwinamo wa kaskazini.