Japan is setting up a US $40 millionlaser-based monitoring station -Keystone - to help predict earthquakes. It will he set up around theTokyo Bay area which lies at thejunction of three giant tectonicplates on the earth's crust. Laserbeams are bounced off from satellitereflectors and the time taken for thereturn of the pulse is recorded. Datacombined with the direction inwhich the laser was fired reveals theexact position of the satellite. Reversing the calculations can determinewhether two plates am moving relative to each other and if they are, atwhat rate to predict the quake (NewScientis4 Vol 148, No 2005).