The 1843 event was followed by eruptions in 1849 , 1851 , 1852 , and 1855 , with the 1855 flows being particularly extensive . 1859 marked the largest of the three historical flows that have been centered on Mauna Loa 's northwestern flank , producing a long lava flow that reached the ocean on Hawaii island 's west coast , north of Kīholo Bay . An eruption in 1868 occurred alongside the enormous 1868 Hawaii earthquake , a magnitude eight event that claimed 77 lives and remains the largest earthquake ever to hit the island . Following further activity in 1871 , Mauna Loa experienced nearly continuous activity from August 1872 through 1877 , a long-lasting and voluminous eruption lasting approximately 1,200 days and never moving beyond its summit . A short single-day eruption in 1877 was unusual in that it took place underwater , in Kealakekua Bay , and within a mile of the shoreline ; curious onlookers approaching the area in boats reported unusually turbulent water and occasional floating blocks of hardened lava . Further eruptions occurred in 1879 and then twice in 1880 , the latter of which extended into 1881 and came within the present boundaries of the island 's largest city , Hilo ; however , at the time , the settlement was a shore-side village located further down the volcano 's slope , and so was unaffected
1868 Hawaii earthquake
1868 Hawaii earthquake
Mauna Loa