▁py ro cl astic ▁sur ge ▁and ▁flow ▁sed iments ▁that ▁vary ▁in ▁thick ness ▁region ally . ▁ ▁The ▁er u ption ▁is ▁estimated ▁to ▁have ▁had ▁a ▁Vol can ic ▁Ex pl os ivity ▁Index ▁of ▁ 7 . ▁It ▁had ▁roughly ▁four ▁times ▁the ▁energy ▁of ▁the ▁ 1 8 8 3 ▁Krak ato a ▁er u ption . ▁An ▁estimated ▁ ▁of ▁py ro cl astic ▁tra chy and es ite ▁was ▁e ject ed , ▁we igh ing ▁approximately ▁ 1 . 4 × 1 0 1 4   kg . ▁This ▁has ▁left ▁a ▁cal der a ▁meas uring ▁ ▁across ▁and ▁ ▁deep . ▁The ▁density ▁of ▁fallen ▁ash ▁in ▁Mak ass ar ▁was ▁ 6 3 6   kg / m 3 . ▁Before ▁the ▁explos ion , ▁Mount ▁Tamb ora ▁was ▁approximately ▁ ▁high , ▁one ▁of ▁the ▁tall est ▁pe aks ▁in ▁the ▁Indones ian ▁arch ip el ago . ▁After ▁the ▁er u ption ▁of ▁ 1 8 1 5 , ▁the ▁maximum ▁elev ation ▁has ▁been ▁reduced ▁to ▁. ▁ ▁The ▁ 1 8 1 5 ▁Tamb ora ▁er u ption ▁is ▁the ▁largest ▁and ▁most ▁dev ast ating ▁observed ▁er u ption ▁in ▁recorded ▁history ; ▁a ▁comparison ▁with ▁other ▁major ▁er u ptions ▁is ▁listed ▁below . ▁The ▁explos ion ▁was ▁heard ▁ ▁away , ▁and ▁ash ▁depos its ▁were ▁registered ▁at ▁a ▁distance ▁of ▁at ▁least ▁. ▁A ▁pitch ▁of ▁darkness ▁was ▁observed ▁as ▁far ▁away ▁as ▁