Bigger is not always better and the Quake Catcher Network project, presenting at the Asia@home Hackfest, is one clear example. With minimal processing requirements compared to other volunteer computing projects, its results enable large-scale impact for earthquake mitigation. The project was presented by Carl Christensen (Chief Software Architect) and Elizabeth Cochran (Project Leader). Chris describes his project as a low CPU-distributed sensor network.
The project uses small remote sensors, MEMs (micro-electromechanical-systems) that contain accelerometers, which measure the acceleration or change of velocity of a device in a specific space. These sensors are located in USB sticks, the latest smart phones, modern laptops and even Nintendo Wii controllers. MEMs are used as basic sensors to detect ground tremors and are essential in early detection of earthquakes, magnitude and tracking propagation of their waves. With enough sensors in an area, an earthquake early-warning system can also be set-up.
Each MEM sensor on the Quake Catcher Network is not of the highest quality (10 or 12 bits), but what they lack in sensitivity, they make up for in simplicity. They are very easy to set-up. With enough MEMs in a given area - say 300 - they can function as one large high-resolution seismic detector. This is not all; Elizabeth said they are ordering higher quality MEMs – 16 to 24 bit – which will add to the network’s sensitivity of earth-born tremors. At $50 a pop, this also makes them low-cost and scalable to enable the network to grow.
The data transfer rate of each sensor is small too. The data used are ASCII plain text files and JPEGs of the seismic records collected by volunteers on the project. The Quake Catcher Network has already proved its worth. On 4th September 2010, a 7.1 magnitude earthquake hit Christchurch in New Zealand. The Quake Catcher Network pre-emptively placed 300 sensors in the area before the earthquake struck. They were set-up by graduate students and New Zealand residents who were recruited through local radio. Scientists gained valuable information about the seismic impact of the earthquake.
Elizabeth mentioned that since the recent earthquake in Japan, there has been more interest in her project. Even Taiwan’s seismologists have been promised more funding for installing subterranean borehole stations to detect earthquakes. Elizabeth states that it is a constant struggle to keep peoples’ attention for long enough to understand how important her work is. It is not a sustainable way for earthquake monitoring. Long term ‘attention’ is needed, so that better detection systems can be set up for future disasters.