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Researchers in Taiwan to use volunteer computing to visualise earthquakes
28 March 2011
Researchers in Taiwan are planning to use volunteer computing to visualise the motion of earthquakes after they occur. They hope this will cut the time of creating ‘shake movies’ from a few hours to just minutes, providing valuable information to rescuers once an earthquake has occurred.
As recent events in Japan have shown, earthquakes and their effects can have devastating consequences. For those countries located on the so-called Ring of Fire, detailed information on seismic events is vital for rescue efforts, education and outreach as well as for research into future events.
Shake movies play an important part in this effort. As animations which show the ground motion of seismic events, shake movies simulate what you feel on the ground during an earthquake. They provide information as to where the strongest shaking has occurred, helping to ensure rescue efforts and resources are directed to where they are most needed.
Researchers create shake movies by performing calculations on models of earthquakes as well as the earth’s structure. However the production process is computationally intensive, taking a few hours to create a movie on a large computing cluster.
In order to cut down the time taken to create these movies, researchers at the Institute of Earth Sciences at Academia Sinica, Taipei, plan to use volunteers to donate idle computing cycles through a new initiative called called Shakemovie@home. The initiative follows in the footsteps of other successful volunteer computing projects such as SETI@home, which searches for extra-terrestrial signals among radio telescope data.
In Shakemovie@Home volunteers’ computers will be used to retrieve essential functions needed to create new shake movies. Called Green’s functions, these elements are a key part of creating shake movies but can take a long time to calculate for every event. However as Green’s functions depend only on the earth’s model, not on the earthquakes themselves researchers can compute, save and store them in advance, simply retrieving them as and when they are needed.
As the retrieval process is simple to carry out, Academia Sinica researchers plan to farm this out to volunteers who have signed up to Shakemovie@Home. By simply retrieving, rather than calculating the Green’s function every time a new shake movie is made they will cut down the time taken from a few hours to just minutes.
“Shake movies need to be both accurate and fast so that rescue efforts can be better directed and resources better allocated. By distributing this task to volunteers to computers at home we can get a better and faster way of making shake movies. Now we have shake movies in a few hours but with volunteer computing we could have it in minutes.” says Professor Li Zhao of the Institute of Earth Sciences, Academia Sinica and leader of Shakemovie@home.
The surface topographic map of Taiwan with 30 arc-second resolution obtained from GTOPO30 released by the U. S. Geological Survey. Labels inside the map indicate the main geological provinces: the Backbone Range (BR); the Hsueshan Range (HR); the Western Foothills (WF); the Coastal Range (CR); and the Hengchun Peninsula (HP). The beach ball shows the location and focal mechanism the March 4, 2010, Jiashian earthquake in southern Taiwan.
Plots of the P-wave speed at four depths in the 3-D model for Taiwan by Wu et al. (2007). High and low wave speeds are indicated by warm and cool colors, respectively.
Z-component Peak Ground Velocity map of the Jiashian earthquake obtained from finite-difference simulation using the topography and structure models shown in Figs.1 and 2. Wu, Y.-M., C.-H. Chang, L. Zhao, J. B. H. Shyu, Y.-G. Chen, K. Sieh, and J.-P. Avouac , Seismic tomography of Taiwan: Improved constraints from a dense network of strong motion stations, Journal of Geophysical Research, vol.112, B08312, 2007.