Kikai caldera (dotted outline) is mostly below sea level. Iōjima in on its northern rim.
By Batholith - Topographic data: NASA's SRTM-1 30m Mesh (ver.3 2014) Rendering software: KASHMIR 3D, Public Domain, Link
A real catastrophe leaves evidence. In prehistoric Japan, an enormous volcanic eruption left a recognisable layer of ash, devastated ecosystems and disrupted human communities. Thousands of years later, archaeologists can still investigate its consequences. Yet the supposedly global catastrophe described in Genesis — a flood intended to destroy almost all terrestrial life — finds no corresponding place in Japan’s long archaeological history. The contrast could hardly be more awkward for biblical literalism.
The real disaster was the Kikai-Akahoya eruption, which occurred about 7,300 years ago, approximately 5300 BCE. That places it roughly three millennia before the Flood date of 2348 BCE in Archbishop Ussher’s chronology, and even before his supposed creation of the world in 4004 BCE. Japan was already inhabited by Jōmon communities who obtained their food through hunting, fishing and gathering. These were real people living in established societies, confronting a natural disaster in a world that, according to that biblical timetable, did not yet exist.
Now, an international team has investigated how those communities responded. Their findings, published in Science Advances reveal a more complicated history than either universal collapse or undisturbed survival. Southern Kyushu was already experiencing population decline before the eruption, whereas population growth in northern Kyushu continued through the disaster and its aftermath. Some more distant regions experienced stagnation or decline.
How can researchers reconstruct population changes without written records or a prehistoric census? They used radiocarbon dates from archaeological remains as an indirect measure of human activity, analysing their distribution through time and across the landscape with Bayesian statistical models. The underlying principle is that larger populations generally leave more traces of occupation that can subsequently be recovered and dated. Such evidence provides estimates of demographic trends rather than exact headcounts, and its interpretation must allow for dating uncertainty and the limitations of the archaeological record.







































