Reconstruction of the 2018 tsunamigenic flank collapse and eruptive activity at Anak Krakatau based on eyewitness reports, seismo-acoustic and satellite observations

•Reconstruction of the eruptive activity using remote geophysical data and personal account of eyewitnesses.•Intense eruptive activity started around eight hours prior to the collapse of the edifice, and continued for days afterward.•Three distinct eruptions observed by eyewitnesses and in satellite imagery between collapse and sustained Surtseyan activity.•Detailed sequence of activity at Anak Krakatau from December 19th to 31st using remote monitoring and eyewitness account.