Do supernovae produce powerful gravitational waves? I would think that the amount of energy produced by one supernova is much more than a pair of colliding black holes, no? Wouldn't that much material and energy output from the explosion generate a powerful gravitational wave?
Actually the peak luminosity for the first binary black hole merger LIGO detected was $3.6 \times 10^{49} \,\text{Watts}$ (source). Whereas the brightest supernova ever recorded was ASASSN-15lh which had a peak luminosity of $2 \times 10^{38} \,\text{Watts}$ (source). In fact the energy radiated by the binary black hole merger during the $0.2 \,\text{s}$ it took to merge was over 10 times the combined luminosity of the observable universe (source).
This translates to the total energy emitted to be $5.4 \times 10^{47} \,\text{J}$ for the black hole merger and $(1.1 \pm 0.2) \times 10^{45} \,\text{J}$ for the ASASSN-15lh supernova. So as you can see, the binary black hole merger released around 100 times more energy than the brightest known supernova.
In relation to the gravitational waves emitted by supernovae, their wave-forms are not as well understood as the &quot;chirps&quot; you get from merging black hole binaries, however they are still expected to be strong enough to be detected in the local universe.