Everything that is black is dried lava. The state of Hawaii is a chain of islands created by volcanic eruptions over time. This is the "Big Island" (this specific island is also named Hawaii, so to avoid confusion with this specific island vs. the state as a whole, it is referred to colloquially as "the big island.")

You can read more about the creation of Hawaii here.

The Big Island is currently the only Hawaiian island with an active volcano, and, yes, it does continually spew lava. "Vog" (volcanic fog) and houses in the way of the lava flow are daily threats. Vog is experienced through many of the islands, not just the big one, because of the winds. But the lava flow is only on the big island. Both these weather effects are covered by the news. The lava flow is not so much an "eruption," as it is more of a slow ooze, but it is still a huge issue that everyone on the island must be aware of. Lava flow conditions are updated throughout the day, similar to weather warnings for other things like storms and floods. They're updated online, the news, and through the radio. Everyone is aware even if they are not physically in view of the lava flow.

That being said, the big island is, well, big, and because it's a slow ooze, it's still fairly safe as long as you don't touch hot lava. The areas in the flow have been closed and people are not allowed there. People with homes in the direction of the lava flow have ample time to prepare to leave/move/etc.

All this being stated, I do not live on the Big Island, so this information is not first hand from me. It's just what I know by association. I live on Oahu, which is the most populated island and is home to the state's capital, Honolulu. We can get Vog here, though it's never personally affected me, but we do not have to deal with lava flow or volcanic eruptions. So, in this way, it doesn't affect me in the slightest.

I took these photos in my gallery when I visited the big island a couple weeks ago. I didn't have a problem with Vog and I was not able to get close enough to the lava flow to be in any danger. The only thing that was kinda weird about the whole trip was the periodic radio reports about the lava flow while driving. Some roads were closed off in the volcanoes national park as well, which made getting around a bit longer because you had to take the long way, but otherwise it was no big deal.

Hope that answers everything. =)