This is coolbert:
Thanks to a serendipitous discovery we have this regarding the massive artillery barrage [rocket artillery included] - - that "Sea of Fire" as promised by the North Korean:
Emphasis in all cases mine! Massive artillery barrages extraordinary and sustained, apocalyptic in nature, literally earth shattering:
"In the introduction to his book, The Red God of War, British military analyst Chris Bellamy vividly
describes some of the effects of massive artillery barrages. Basing his description on eyewitness reports from several wars, he recounts the 'sheer horror' and the 'sense of hopelessness' artillery barrages create among those on the receiving end. For soldiers subjected to massive artillery barrages, artillery is a 'monstrous, apparently unstoppable machine, slicing mechanically through earth, rock, flesh, bone and spirit.' The 'psychological effect multiplies its cold lethality many times.'"
"Artillery oppresses, jars, stuns and disorientates the enemy and lifts the morale of its own troops.
Artillery and rockets provide the greatest firepower and sear a path for infantry, mechanized forces and armour both physically and spiritually. Throughout the centuries, no army has understood this better than the Russian."
AND PERHAPS EVEN BEYOND THE RUSSIAN THE NORTH KOREAN!!
Massive artillery barrages the archetypes of which and as might have been found:
* The Spring Offensives of the German .
And as employed by the Soviet [Russian]:
* The Moscow Counter-offensive .
* The crossing of the Oder .
* The crossing of the Teltow Canal 
Massive and overwhelming numbers of artillery pieces, not only that count of tubes firing but ammunition expended in a prodigal manner, almost limitless resources used lavishly and without regard to expenditure. At that crossing of the Teltow Canal the Soviet massing three hundred guns as arrayed per mile [1.6 kilometers]!!
Devoted readers to the blog, you take it from there!