Complexities of Indonesia’s Disaster and Some Similarities in New Zealand

From Scientific American: Indonesian Tsunami Was Powered by a Deadly Combo of Tectonics and Geography. The magnitude 7.5 earthquake that touched off the tsunami occurred amid a complex puzzle of tectonic plates.

Thanks to Ian McLean of New Zealand for this citation. He says that NZ also has similar tectonic conditions.  Here are some of his observations about the seismic conditions and risk in New Zealand.

What I found particularly interesting was the fact that the earthquake occurred in a transition zone. To the west of this zone one plate subducts, and to the east of the zone the plates abut pushing up mountain ranges.

The configuration is similar to the zone in New Zealand where the Kaikoura sequence of earthquakes occurred.. To the north the Pacific plate subducts the Indo-Australian plate; and to the south the plates abut, pushing up the Southern Alps.

In the transition zone is a complex jumble of faults. Several of these ruptured sequentially during the Kaikoura sequence. The damage was unexpectedly severe, especially in Wellington.

But NZ  still awaits with apprehension earthquakes along the plate boundaries to the south and north of the transition zone. To the south , the Alpine fault has reached its mean return period. In the north, knowledge about the HIkurangi subduction zone was sparse, but substantial research is now being done.

Ian McLean is a former Chair of NZ Earthquake Commission, and has advised on catastrophe insurance schemes around the world, including helping to form the schemes in Turkey and Romania through the World Bank.

San Francisco’s Big Seismic Gamble

From the NYTimes: San Francisco’s Big Seismic Gamble

San Francisco lives with the certainty that the Big One will come. But the city is also putting up taller and taller buildings clustered closer and closer together because of the state’s severe housing shortage. Now those competing pressures have prompted an anxious rethinking of building regulations. Experts are sending this message: The building code does not protect cities from earthquakes nearly as much as you might think.

Progress in Predicting Major Earthquakes

Article on Predicting Major Earthquakes.

A Nagoya University-led team reveals the mechanisms behind different earthquakes at a plate boundary on the west coast of South America, shedding light on historical seismic events and providing a foundation for risk prediction tools to assess the likelihood of earthquakes and tsunamis striking this region and their potential periodicity and intensity.

Earthquake Early Warning for Transit Systems

From the Homeland Security Newswire: Earthquake early warning vital for city transit. |

Although no one can reliably predict earthquakes, today’s technology is advanced enough to rapidly detect seismic waves as an earthquake begins, calculate the maximum expected shaking, and send alerts to surrounding areas before damage can occur. This technology is known as “earthquake early warning” (EEW). An EEW system called “ShakeAlert” is being developed and tested for the West Coast of the United States.

“EEW is a game changer with respect to postdisaster recovery,” Johnson said. “By using EEW to minimize derailments, lives will be saved, injuries will be reduced, and the impacts to a postdisaster-stressed medical system will be minimized.”