![]() ![]() ![]() The acquisition of 1221 thermal data and 1156 SO2 emission data was performed using MODIS and OMI. The use of different remote sensing techniques allowed the acquisition of thermal data, SO2 emission data, structural data and the identification and analysis of the eruptive events that occurred on Anak Krakatau in the period from 1° January 2016 to 28 February 2019. The goal of the study was to monitor and analyze changes of the volcanic edifice and to try to understand causes that may have predisposed and triggered the sector collapse. The study was focused on the Anak Krakatau sector collapse that occurred on 22 December 2018 in the Sunda Strait (Indonesia). ![]() This long-term seismic quiescence might have caused lock up of stresses that resulted in highly devastating 26 December 2004 earthquake. However, north of 2°N, the low deformation velocities in the offshore Sumatra can be attributed to the absence of significant earthquakes during the period of investigation. The deformation pattern in the offshore Sumatra indicates that the Mentawai fault partly accommodates motion due to oblique subduction and suggests local interaction of the Investigator Fracture Zone near the equator. While seismic slip rates match well with the geological or GPS derived slip rates between 0° and 2°S along SFZ, the values are much lower for the fault segments north of equator. Crustal deformation rates (1900-2000) estimated for the Sumatra-Java arc region highlight (i) large variations in dextral shear motion (seismic slip) from 1 mm/yr to 29 mm/yr along the Sumatran Fault Zone (SFZ), (ii) dominantly compression with deformation velocities as high as 19 mm/yr near the equator along offshore Sumatra fore-arc and, (iii) dominance of compression (average 19 mm/yr) in the western part of offshore Java fore-arc that gradually changes to extension (average 3 mm/yr) towards east. ![]()
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