Hawaii, a paradise of lush islands and fiery volcanoes, is no stranger to seismic activity. Its unique location over a volcanic hotspot in the Pacific has shaped the islands for millions of years, building them up from the ocean floor.
But along with beauty and wonder, this dynamic environment also brings natural hazards—including earthquakes. While small tremors are frequent across the islands, one historic quake stands out above all others: the largest earthquake to ever strike Hawaii, remembered for its power, destruction, and lasting impact.
The Legendary 1868 Great Hawaii Earthquake
The title of Hawaii’s biggest earthquake goes to the 1868 Great Hawaii Earthquake, a massive temblor that shook the Big Island on April 2, 1868. With an estimated magnitude of 7.9, this quake is the strongest ever recorded in the Hawaiian Islands’ history. Though it happened before the era of modern seismometers, detailed historical accounts and geological evidence have allowed scientists to reconstruct its immense force and effects.
This earthquake was centered on the southeastern flank of Mauna Loa, one of the world’s largest active volcanoes. At the time, Mauna Loa was already showing signs of unrest, and when the earthquake struck, it triggered deadly landslides, tsunamis, and widespread destruction across the region.
What Caused the 1868 Earthquake?
Unlike the earthquakes caused by tectonic plate collisions along the Pacific Rim, Hawaii’s quakes are often tied to volcanic processes. In the case of the 1868 quake, scientists believe it was related to the movement along a large fault at the base of Mauna Loa. This massive volcano’s south flank slides gradually seaward, and sometimes the accumulated strain is suddenly released in a powerful earthquake.
The 1868 event is thought to have originated deep within the crust, where the sliding flank met resistance until it violently ruptured. This rupture sent shockwaves across the island, toppling stone walls, cracking roads, and shaking the ground so violently that people reportedly couldn’t stand upright.
Devastating Consequences Across the Island
The shaking from the 1868 quake caused immediate destruction. Reports from the time describe churches, homes, and buildings collapsing, while landslides thundered down the slopes, burying villages and killing dozens. In the Ka‘ū district, one of the hardest-hit areas, a massive landslide killed 31 people in a single instant.
But the earthquake’s impact didn’t stop there. It also generated a local tsunami that rushed ashore, destroying coastal villages and killing at least 46 people along the Punaluu and Honuapo shorelines. In total, more than 77 lives were lost, and countless others were left injured or homeless. For a sparsely populated island chain in the 19th century, this was a catastrophic blow.
The Long Shadow of Aftershocks and Volcanic Activity
The 1868 earthquake was followed by weeks of strong aftershocks, some of which were powerful enough to be considered major quakes on their own. These aftershocks further rattled nerves and damaged weakened structures.
At the same time, volcanic activity on Mauna Loa surged, with lava fountains erupting from fissures and flowing down the slopes. While the link between the earthquake and the volcanic eruptions is still debated, it’s clear that this period marked one of the most geologically active times in Hawaii’s recorded history.
How Scientists Studied the Quake Without Instruments
Since the earthquake occurred before the development of modern seismology, scientists have pieced together its story using written eyewitness accounts, geological surveys, and historical research. Letters, diaries, and newspaper reports describe the strength of the shaking, the extent of the damage, and the sequence of events.
Geologists have also studied landslide scars, tsunami deposits, and fault movements to estimate the quake’s size and mechanics. While some early estimates placed it at magnitude 7.5, more recent studies suggest it was likely closer to magnitude 7.9—comparable to some of the most destructive earthquakes worldwide.
Why the 1868 Earthquake Still Matters Today
The Great Hawaii Earthquake of 1868 isn’t just a historical curiosity—it’s a critical reminder of the islands’ ongoing seismic risks. Although such massive earthquakes are rare, Hawaii continues to experience moderate quakes regularly, and the potential for another large quake remains.
Modern communities on the Big Island are larger and more developed than in 1868, meaning the stakes are even higher. A similar earthquake today could damage infrastructure, trigger deadly tsunamis, and put thousands of people at risk. That’s why geologists and emergency planners closely monitor the volcanic flanks and educate residents about earthquake preparedness.
Lessons Learned and Preparedness for the Future
Hawaii has taken steps to improve earthquake and tsunami readiness, including early warning systems, tsunami evacuation routes, and strict building codes designed to withstand seismic forces. Scientists now monitor ground deformation on Mauna Loa with GPS and satellite data, looking for signs of flank instability.
Residents are encouraged to prepare emergency kits, secure heavy furniture, and know evacuation plans, especially in coastal and high-risk areas. While the exact timing of the next big quake can’t be predicted, being prepared can save lives and reduce harm when it strikes.
Conclusion
The 1868 Great Hawaii Earthquake stands as a powerful chapter in the islands’ history. With its massive magnitude, deadly consequences, and lasting geological impact, it serves as both a sobering reminder of nature’s power and a call to readiness. As Hawaii continues to thrive amid its breathtaking beauty and natural dynamism, the lessons of the past help guide a safer future for all who call these islands home.
