The shaking on Sangihe Island was accompanied by an intense, deep rumble that residents described as coming from the earth itself. People could not stand. Houses built on swampy ground rose from their foundations and collapsed sideways. In the towns of Enemawira, Peta, and Tabukan, many buildings fell. Schools, homes, and businesses collapsed in Tamako. At Manganitu and Kendahe, the damage was severe. Along the rocky coastline, rock falls were widespread, and fractures opened in the ground, some of them ejecting water under pressure. Twenty people died on Sangihe from the shaking alone -- crushed by collapsing structures or struck by falling rock. But the worst was yet to come. In the Menalu area, the coastline itself subsided. The sea rushed inland, inundating low-lying ground that had been dry land minutes before. Surviving residents were forced to relocate entirely. Coastal subsidence also struck Peta Bay, Tamako, and Tabukan.

At Menalu Bay, a massive quantity of material broke loose from the heights and plunged into the water. West of there, a mudflow cascaded down from Endongo Hill toward the village below. The flow was fast, heavy, and inescapable. It buried 117 villagers and 29 houses under a thick layer of debris. The mudflow then dammed a river, which overflowed and washed away bridges in Manganitu. In total, the earthquake killed 138 people across the Sangihe Islands -- 20 from the shaking itself, the rest from the mudflow that the shaking unleashed. The dead were overwhelmingly ordinary villagers: farmers, fishermen, families who lived in the shadow of a hill that had given them no reason for concern until that morning. Their village simply ceased to exist, buried under material that the earthquake shook loose from slopes saturated by tropical rains.

The earthquake's effects extended well beyond Sangihe. On Siau Island to the south, one person died and several were injured. Ground fractures, avalanches, and rockfalls scarred the landscape, though Siau was spared the coastal subsidence that reshaped Sangihe's shoreline. Many brick buildings were ruined, and some traditional huts sank to one side as the ground shifted beneath them. People reported being unable to stand during the shaking -- the same experience described on Sangihe, suggesting uniformly violent ground motion across the island chain. Similar environmental effects and structural damage occurred in the Talaud Islands farther north, though remarkably no casualties were reported there. The earthquake was preceded by foreshocks, but in 1913 there was no system in place to interpret such warnings or alert the population. The shaking simply arrived.

The Sangihe Islands sit on the tectonic boundary between the Celebes Sea and the Molucca Sea, straddling an arc of volcanic islands that marks one of the most seismically active zones on Earth. The 1913 earthquake was not the first to devastate these islands, nor would it be the last. The same geological forces that created the Sangihe archipelago -- subduction, volcanism, the restless grinding of tectonic plates -- periodically destroy what has been built upon it. Mount Awu, the active volcano on Sangir Besar, has erupted catastrophically multiple times in recorded history. The 2023 Mindanao earthquake, centered not far to the north, demonstrated that the same fault systems remain fully capable of producing destructive events. For the people of the Sangihe Islands, the 1913 earthquake is not ancient history. It is a reminder of where they live and what the earth beneath them can do.