Fig. 4
Sand/silt/debris flowslide and debris avalanche in TBJ after rains. Photo a are flowslides that were connected with a flat surface on top, which allowed infiltration and runoff. b A typical mitigation work for a TBJ slope with a flat surface on top, including drainage system and grass cover. If not regularly maintenance is made failure happens. c, d Photos belong to the same location and is a typical example of damage connected with a flowslide during Hurricane Ida in 2009 (photo c); that killed 3 persons inside the house in photo d. Photos e, f debris flowslides/debris avalanches in the hillsides of Ilopango Caldera (Hurricane Ida 2009)