Mar

6

oarfishOarfish Omen Spells Earthquake Disaster for Japan

This rash of tectonic movements around the Pacific "Rim of Fire" is heightening concern that Japan - the most earthquake-prone country in the world - is next in line for a major earthquake.

Those concerns have been stoked by the unexplained appearance of a fish that is known traditionally as the Messenger from the Sea God's Palace.

The giant oarfish can grow up to five metres in length and is usually to be found at depths of 1,000 metres and very rarely above 200 metres from the surface. Long and slender with a dorsal fin the length of its body, the oarfish resembles a snake.

In recent weeks, 10 specimens have been found either washed ashore or in fishing nets off Ishikawa Prefecture, half-a-dozen have been caught in nets off Toyama Prefecture and others have been reported in Kyoto, Shimane and Nagasaki prefectures, all on the northern coast.

According to traditional Japanese lore, the fish rise to the surface and beach themselves to warn of an impending earthquake - and there are scientific theories that bottom-dwelling fish may very well be susceptible to movements in seismic fault lines and act in uncharacteristic ways in advance of an earthquake - but experts here are placing more faith in their constant high-tech monitoring of the tectonic plates beneath the surface.

Market wise — maybe the appearance of strange stocks at high levels indicating impending reversal to the mean.

Pitt Maner III adds:

This following is an interesting abstract of a paper that is suggestive of the potential triggering of additional earthquakes after a strong earthquake thousands of miles away. The time scale is in years and the number of variables involved for any particular area and/or fault regimes would be quite large. The Cal Berkeley Seismology site mentions a statistic for the Heyward Fault nearby of a 60% chance of a 6.7 mag. event in the next 35 years — so you have to wonder if the odds are slightly changed by large global seismic events. California, however, appears to be one of the most prepared places for the inevitable temblor. Analogies to financial "stress tests" and regional crisis? With cracks appearing in structures after "torture testing"…

From an article on nature.com:

Fault strength is a fundamental property of seismogenic zones, and its temporal changes can increase or decrease the likelihood of failure and the ultimate triggering of seismic events. Although changes in fault strength have been suggested to explain various phenomena, such as the remote triggering of seismicity1, there has been no means of actually monitoring this important property in situ. Here we argue that 20 years of observation (1987–2008) of the Parkfield area at the San Andreas fault have revealed a means of monitoring fault strength. We have identified two occasions where long-term changes in fault strength have been most probably induced remotely by large seismic events, namely the 2004 magnitude (M) 9.1 Sumatra–Andaman earthquake and the earlier 1992 M = 7.3 Landers earthquake. In both cases, the change possessed two manifestations: temporal variations in the properties of seismic scatterers—probably reflecting the stress-induced migration of fluids—and systematic temporal variations in the characteristics of repeating-earthquake sequences that are most consistent with changes in fault strength. In the case of the 1992 Landers earthquake, a period of reduced strength probably triggered the 1993 Parkfield aseismic transient2, 3, 4, 5 as well as the accompanying cluster of four M > 4 earthquakes at Parkfield. The fault-strength changes produced by the distant 2004 Sumatra–Andaman earthquake are especially important, as they suggest that the very largest earthquakes may have a global influence on the strength of the Earth's fault systems. As such a perturbation would bring many fault zones closer to failure, it should lead to temporal clustering of global seismicity. This hypothesis seems to be supported by the unusually high number of M 8 earthquakes occurring in the few years following the 2004 Sumatra–Andaman earthquake.

This Berkeley website document gives a good overview of the seismology field and future "grand challenges." Some really nice graphics.


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