MENTAWAI QUAKES JOLT VISITING TSUNAMI WARNING GROUP

Ancient chicken on a Chinese roof. In search of a new warning system

Wednesday - Two quake measuring 5.3 and 4.5 jolted Padang in the early hours of the morning. For some reason they did not trigger the normal automatic email to our server but the quakes are listed on the USGS web site today. By co-incidence ELM headquarters hosted lunch for 25 members of a UN sponsored delegation visiting Padang to discuss and review tsunami readiness in the area and to collaborate on the proposed Indian Ocean Tsunami warning system.

The group included:

Praveen Pardeshi - UN Inter-Agency Secretariat for the International Strategy for Disaster Reduction (UN/ISDR), Switzerland

Dr Walter Mooney - Lead Co-ordinator for USGS activities related to the Indian Ocean Tsunami Warning System. California

Laura Kong - Director - International Tsunami Information Centre, Hawaii.

Dr Mooney shed some light on one of the mysteries that emerged after the Aceh tsunami. Many survivors mentioned a series of 3 extremely loud explosions that occurred just after the quake and before the tsunami. Some thought that underwater volanoes had erupted and others said that they thought underground gas had exploded. Dr Mooney believes that the explosions were most likely caused by a massive release of methane from ice bound compounds trapped for millenium in the depths of the ocean trenches in the vicinity of the rupture. The displacement of the sea bed and the heat released could have ignited the released gas spontaneously as the fault line ruptured.

I did not think to ask at the time but it could be possible that the explosions occurred at the sea bed or underwater and the expansion of gas may help explain the enormous scale of the tsunamis. For this to happen, Oxygen would have to be present in the gas released. It is unlikely to be the reason behind the burns we observed and the many accounts of very hot and oily black water in the second wave. Could it be possible that there was localized venting of subterranian hydrocarbon pockets heated by the stresses released by the quake?

Dr Mooney also discussed the complexity of relying on strange animal behavior as a quake precusor to watch for. He recounted visiting China where officials and scientists were very proud that they evacuated a city just before a devastating quake. Dr Mooney was observing graphs of statistics gathered prior to the quake and saw one line jump just hours before the quake hit. "Yes", the Chinese officials confirmed, "that line represents the number of chickens on the roof reported by residents in the area".

Perplexed at why chickens on the roof might be significant, Dr Mooney asked the obvious question. One Chinese official looked a little annoyed that a World class scientist would need to ask such an obvious question but he patiently explained.... "Because they were afraid of the snakes" as though he were speaking to a rather dull student.

"Snakes?" Dr Mooney was now completely lost.

The Chinese official shook his head in disbelief. "Yes, the snakes all came out of their holes because the water table rose and flooded their burrows" came the now slightly impatient reply.