Now a team of researchers think they’ve found it, buried beneath a lava bed in Laos.

The team, led by Kerry Sieh, a geologist at the Earth Observatory of Singapore, published its evidence last week in Proceedings of the National Academy of Sciences. While some researchers suggest that additional fieldwork is needed to confirm the findings, these results provide important clues toward piecing together a catastrophic encounter between Earth and a fiery visitor from space.

Dr. Sieh has been hunting for the crater for years, but many leads turned out to be dead ends. While most scientists agree the meteorite impact likely occurred in Southeast Asia, that presents a puzzle.

Many ancient impact craters have disappeared from Earth’s surface as a result of volcanic, tectonic and other erosional forces. But most places in Southeast Asia experience low rates of erosion and sedimentation, insufficient to have erased such a large crater in a relatively short amount of time.

However, there’s at least one exception: a Delaware-sized plateau near the Mekong River in southern Laos. Here, volcanic eruptions have created lava beds up to 1,000 feet deep. That’s thick enough to hide a large crater, the scientists realized. The hunt was on.

Dr. Sieh and his colleagues began by studying data showing that Australasian tektites contain elements characteristic of the Laotian volcanic field. The scientists also age dated the lava flows. Some predated the impact while others postdated it. That makes sense, said Dr. Sieh, since the lavas that buried the crater must be younger than the impact and the lavas that were incorporated into the tektites must be older.