Secondary explosions - another shortcoming of international law

Anyone who has seen the IDF aerial videos of airstrikes in Gaza has seen the initial IDF charge explosion, followed by (often much larger) secondary explosions from the bombs and weapons that were stored in the targeted facilities. Here's one from a terror mosque that was targeted today:


And this one was from an attack at an underground rocket storage facility:


The problem is that it appears that international law would prohibit Israel from targeting these clearly military objectives - because while Israel believes that they house explosives, and the IAF can calibrate their bombing to the minimum amount possible, there is no way to know how large the secondary explosions will be. And the secondary explosions often kill more people than the primary explosions, judging from the relative sizes of the explosions in the video.

Under international law, Israel must be careful when targeting facilities in civilian areas. Geneva Protocol 1 par. 48 states:

In order to ensure respect for and protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives.

Paragraph 51 includes details of what is not allowed:

4. Indiscriminate attacks are prohibited. Indiscriminate attacks are: (a) those which are not directed at a specific military objective; (b) those which employ a method or means of combat which cannot be directed at a specific military objective; or (c) those which employ a method or means of combat the effects of which cannot be limited as required by this Protocol;

and consequently, in each such case, are of a nature to strike military objectives and civilians or civilian objects without distinction.

5. Among others, the following types of attacks are to be considered as indiscriminate: (a) an attack by bombardment by any methods or means which treats as a single military objective a number of clearly separated and distinct military objectives located in a city, town, village or other area containing a similar concentration of civilians or civilian objects;

and

(b) an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.

So while the legality of a military target illegally placed in a civilian area is proportional to its importance, its legality as a target seems to be inversely proportional to the size of a resultant secondary explosion affecting the neighboring civilians. And there is no way to know how large the secondary explosion will be, so there is no way to know ahead of time whether a target is going to blow up the entire neighborhood.

Israel is trying to do everything possible to minimize this problem - sending text messages to residents before a bombing raid so they can get out of the way, and now using sound bombs to startle them into leaving. While this is laudable (perhaps to the point of being foolhardy) there will still be some civilian casualties that "impartial" jurists could interpret as being the result of illegal actions under para 51.4(c) - effects that cannot be limited, because of terrorist action.

As we have seen before, international law needs to catch up to the age of terrorism. The blame for casualties caused by secondary explosions in mosques and private homes used as weapons caches must go squarely to the terrorists who placed them there (endangering residents even when not at war.)

UPDATE: Commenter Amy points to an excellent treatment of fighting terrorists in Gaza and international law. My point is not that Israel is in clear violation, but that Geneva can be interpreted against Israeli actions, which would give terrorists an advantage.