500-year-old lava rock in Hawaii collapses into Pacific Ocean. How earthquakes, waves, erosion brought down the 90-foot-tall sea arch

There’s no choice but to bow down to natural forces. In a similar display of nature’s fury, a lava rock in Hawaii, formed as far back as 550 years ago, recently collapsed into the Pacific Ocean. The 90-foot-tall structure, famously known as the Hōlei Sea Arch, stood in Hawaii’s Volcanoes National Park on the southern coast of the Big Island, dubbed the largest and youngest island of the Hawaiian chain. The colossal sea arch has long been a major landmark on the rugged coastline, drawing tourists in large numbers.

All about Hawaii’s lava rock collapse

According to the United States National Park Service (NPS), the arch was a natural formation created by ancient lava flow that erupted from one of the 6 volcanoes on the island, as quoted by CNN. The lava hit the cliff edges and carved the vault, creating the natural marvel.

While the exact time of the collapse remains undetermined, the NPS revealed that the arch was projecting into the water from the Volcanoes National Park coast on September 23. But 4 days later, on September 27, it had crumbled into the ocean. Reports indicate that the arch might have fallen when the park was temporarily closed during Tropical Storm Nolo, reported BBC.

Why did the lava rock collapse

The NPS on its website shared that the demise of the decades-old lava rock has long been expected, claiming that although the formation is beautiful, its lifespan is temporary. Additionally, the park service noted that earthquakes during the 2018 Kīlauea volcano eruption and summit collapse had already damaged the cliffs near the arch. In 2020, waves from a tropical storm broke off a chunk of rock from the arch’s bottom.

Apart from that, differential erosion, a process in which softer rock wears away faster and more easily than stronger, more resistant rock, also contributed to the collapse of the giant structure. The park staff revealed that they were aware of the incessant battering of waves against the sea arch that would eventually cause it to crumble, although they were not able to predict exactly when this would happen.