Chile Earthquake and Tsunami
A magnitude 8.8 earthquake struck off the coast of Chile late yesterday evening (10:34 PST), killing scores of people in Chile and causing Hawaii to brace for its biggest tsunami since the Alaskan earthquake of 1964.
The tsunami alert went out hours before the first waves, traveling at the speed of a passenger jetliner, were expected to hit Hawaii at 11:19 this morning, local time.
Tourists and coastal residents are expected to wake up to tsunami alarms and evacuation instructions several hours earlier, tsunami authorities told the Associated Press.
The earthquake occurred along the junction of the Nazca and South American tectonic plates, which are colliding off the coast of Chile at a rate of 80 millimeters per year.
The coastline of Chile is one of the most active tectonic zones in the world, with 13 temblors of magnitude 7.0 or greater since 1973, the U.S. Geological Survey reports on its earthquake-monitoring Website.
The GCP event was set for the full 24 hour day of the 27th, which includes 6.5 hours before the main temblor. The result is Chisquare 86852.814 on 86400 df, for p = 0.138 and Z = 1.089.
We have an Egg in Santiago, which was running at the beginning of the earthquake. It continued to run for about 20 hours following the major 8.8 temblor, then stopped recording data. On March 1st, it was restored to operation, and the stored data were sent to the GCP server and added to the archive. The following graph shows the data from the Santiago Egg, ID #2080, in green. The graph also shows not only the 24 hours of the formal GCP event, but the next 24 hours as well. While we know that the signal to noise ratio precludes strong interpretations, both the local Egg, and the 48 hour graph suggest effects on the network consonant with the unfolding picture of a devastating natural disaster.
The next closest egg to Santiago is in Buenos Aires, where people also felt the quake. Egg # 2069 was running during both days, and its data have a trajectory much like that of the network as a whole. The next figure shows the two individual eggs, Santiago and Buenos Aires against the background of the whole network. Again, single events, and data from single eggs can't be interpreted reliably, but we show this picture as an interesting display of the variation in responses.
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.