After starting to write this section we realized that to do it well would repeat much of what already exists on the US Geological Survey’s website related to Hawaiian volcanism. Readers are urged to look over that site before traveling to Hawaii.
One of the main attractions of naturalists to the Hawaiian Islands is to see active volcanism. From early 1983 until 2018 there was almost continuous lava lake or fissure eruptions on the Big Island. This was an unprecedented period of activity in recent history. However, an eruptive phase in 2018 drained the Kilauea lava lake and magma chamber, leading to a major collapse of the Kilauea caldera and a cessation of activity. Currently (2020) there are no volcanic eruptions occurring anywhere in the Hawaiian Islands.
The current lack of active volcanism doesn’t mean there isn’t a lack of interesting volcanic features to see in Hawaii. In fact, one can justifiably argue that conditions are better now to see volcanic landscapes than during the active eruptions. Why? First, there are fewer prohibited zones where you cannot walk, though some areas are still closed until trails and roads are rebuilt. Second, VOG (volcanic gases – mainly sulfur dioxide) is no longer present in large quantities. The air is finally clear after decades of poor air quality and poor visibility.
Note that the volcanos are not dead, not really even dormant. To see this go to the Earthquake page of the Hawaii Volcano Observatory (HVO), which displays weaker earthquakes than the main USGS Earthquake page. There are frequent earthquakes, mostly undetectable by people, below the summit of Mauna Loa and Kilauea and a few other locations. These reflect magma adjustments below the volcanoes.
A US Geological Survey summary of the 2018 Kilauea eruption is found here.