6 mini explosion detected by seismography right before Beirut port explosion

5 explosion exactly 11 sec apart, each one made by a few tons of explosives. then a 6 one and then the big one according to the researchers
data came from a seismic detection system in the sea 70 km from Beirut.
data was available online, but then the site shut down.researchers was able to get the data right before it went down.

for view
needs to be know