Pengguna:Swarabakti/Terjemahan: Perbedaan antara revisi

[[File:Segara Anak.jpg|thumb|right|upright=2.0|Kaldera [[Segara Anak]] sisa letusan Samalas|alt=Sebuah puncak kerucut dan danau kehijauan di dalam sebuah kawah besar]]

 

 

The deposition of these pumices was followed by another stage of pyroclastic flow activity, probably caused by the collapse of the [[eruption column]] that generated the flows. At this time the eruption changed from an eruption-column-generating stage to a fountain-like stage and the caldera began to form. These pyroclastic flows were deflected by the [[topography]] of Lombok, filling valleys and moving around obstacles such as older volcanoes as they expanded across the island incinerating the island's vegetation. Interaction between these flows and the air triggered the formation of additional eruption clouds and secondary pyroclastic flows. Where the flows entered the sea north and east of Lombok Island, steam explosions created pumice cones on the beaches and additional secondary pyroclastic flows.{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|p=7}} [[Coral reef]]s were buried by the pyroclastic flows; some flows crossed the [[Alas Strait]] between Sumbawa and Lombok and formed deposits on Sumbawa.{{sfn|Mutaqin|Lavigne|Sudrajat|Handayani|2019|p=344}} These pyroclastic flows reached volumes of {{convert|29|km3}} on Lombok,{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|p=17}} and thicknesses of {{convert|35|m}} as far as {{convert|25|km}} from Samalas.{{sfn|Lavigne|Degeai|Komorowski|Guillet|2013|p=16744}} The phases of the eruption are also known as P1 (phreatic and magmatic phase), P2 (phreatomagmatic with pyroclastic flows), P3 ([[Plinian eruption|Plinian]]) and P4 (pyroclastic flows).{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|pp=21–22}} The duration of the P1 and P3 phases is not known individually, but the two phases combined (not including P2) lasted between 12 and 15 hours.{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|p=18}} The pyroclastic flows altered the geography of eastern Lombok, burying [[river valley]]s and extending the shoreline; a new river network developed on the volcanic deposits after the eruption.{{sfn|Mutaqin|Lavigne|Sudrajat|Handayani|2019|p=348}} The eruption column reached a height of {{convert|39|-|40|km}} during the first stage (P1),{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|pp=17–18}} and of {{convert|38|-|43|km}} during the third stage (P3);{{sfn|Vidal|Komorowski|Métrich|Pratomo|2015|p=18}} it was high enough that {{chem|link=sulfur dioxide|S|O|2}} in it and its {{sulfur}} [[isotope ratio]] was influenced by [[photolysis]] at high altitudes.<ref name="Whitehill2015"/>