Guatamala's Fuego Volcano Erupts

Guatemala's most violent volcano eruption in more than a century has killed at least 25 people. The Fuego volcano, about 40km (25 miles) south-west of the capital Guatemala City, spewed rock, gas and ash into the sky on Sunday. Fast-moving flows hit villages, killing people inside their homes. Hundreds were injured and many are missing. The country's main airport is closed.

President Jimmy Morales has declared three days of national mourning. In a statement issued late on Sunday, he spoke of the nation's "deep pain" caused by the "irreparable losses" in human lives.

Settlements on the southern slopes of Fuego were buried in the volcanic ash, mud and rocks as the volcano erupted for 16 and a half hours on Sunday. Pyroclastic flows, which are fast-moving mixtures of gas and volcanic matter, rushed down the mountainside and engulfed villages.

Specific Hypothesis and Results

The GCP explorations was set for 16.5 hours beginning at about the time the eruption apparently started. This was around 07:30 UTC, and covers the period reported for the eruption. The result shows a brief spike at the beginning, and a gradual rise (consistent positive deviations) for about 8 hours followed by a similarly consistent fall (negative deviations) for the second half of the period.

Interpretation

The following graph is a visual display of the statistical result. It shows the second-by-second accumulation of small deviations of the data from what’s expected. Our prediction is that deviations will tend to be positive, and if this is so, the jagged line will tend to go upward. If the endpoint is positive, this is evidence for the general hypothesis and adds to the bottom line. If the endpoint is outside the smooth curve showing 0.05 probability, the deviation is nominally significant. If the trend of the cumulative deviation is downward, this is evidence against the hypothesis, and is subtracted from the bottom line. For more detail on how to interpret the results, see The Science and related pages, as well as the standard caveat below.

Standard caveat

It is important to keep in mind that we have only a tiny statistical effect, so that it is always hard to distinguish signal from noise. This means that every success might be largely driven by chance, and every null might include a real signal overwhelmed by noise. In the long run, a real effect can be identified only by patiently accumulating replications of similar analyses.