Shocking Lava
Instant
Requires Shaman
Your Lava Burst and Lava Lash increase the damage of your next
Earth Shock or Flame Shock by 50%, stacking up to 2 times.
Fulmination and Shocking Lava
DO coincide when using Earth Shock.
Also, I'm sure those 2% ES does do not include Fulmination, which essentially is part of Earth Shock and should be added.
Highest ranked elemental in what seems to be a mostly
single target fight 4.6% Fulmination + 1.3% Earth Shock => ~6% of damage done by using Earth Shock, which would be increased via Shocking Lava.