Simultaneous, parallel and multiple EAS events due to Gerasimova‐Zatsepin effect in LAAS experiments

To study the ultra‐high energy cosmic ray composition by making use of the GZ scenario, Large Area Air Shower (LAAS) experiments had been started in 1996 by the collaboration of 7 institutes in Japan. We present here some results of LAAS observations on the GZ event search during the data period from 1996 to January 2007. A brief profile of the potential of LAAS EAS array is also presented.