Samples SiO2 Al2O3 Fe2O3 CaO MgO K2O SO3 P2O5
Anak Krakatau 62.96c 22.25a 4.34a 5.82a 3.02a 0.68c 0.83a 0.64a
Panjang 65.50bc 20.55ab 3.94a 4.81a 2.51a 1.10bc 0.17b 0.64a
Rakata 73.47a 18.14b 2.16b 2.15b 1.42b 1.54a 0.03b 0.55b
Sebesi 66.92b 22.64a 3.64a 1.73b 1.69b 1.32ab 0.08b 0.55b
Minimum 52.66 16.37 0.01 0.00 0.44 0.63 0.00 0.43
Maximum 75.50 31.42 9.75 6.69 4.99 2.00 3.72 0.77
Mean 67.18 21.33 3.55 2.92 1.94 1.24 0.23 0.58
Std. deviation 5.62 3.70 1.63 1.82 0.99 0.39 0.55 0.09