What Volcanologists Do - A LiDAR Study of the Overlook Crater and lava lake at Kilauea volcano, Hawaii

Goal of our Research : Determine how fast the Overlook Crater at Kilauea volcano is growing.

Night view of the 1/2 mile wide Halemaumau crater. The Overlook Crater is a smaller crater inside Halemaumau, and the glow you see here is from the heat of a lava lake reflecting off the plume of gas coming from the lake

Why is this important:  One of the biggest hazards associated with the lava lake are rock falls from the crater walls that land in the lake and cause explosions (Check out the video below one of these explosions!) that have shut down a popular tourist area and endanger volcanologists lives and expensive equipment.  With this project, we are able to predict how much material should fall into the crater with time, although we still can’t predict the size and timing of each rock fall event.

Some Background: Below are a couple of images showing Kilauea volcano and the location of the Overlook Crater and lava lake.  

The Big Island of Hawaii, and the active Kilauea summit.

Below is a closer view of the summit.

The Overlook Crater and lava lake sits inside Haleamaumau crater (1/2 mile wide) which sits in the Kilauea caldera (about 3 miles wide) which sits on top of the 5000' Kilauea volcano

Below is a view of the Overlook Crater and lava lake. It's an amazing place because it's a lava lake in a crater in a bigger crater in a bigger crater on a volcano!! In the picture of the Overlook Crater and lava lake below, you will see two of us working beneath the arrow. 

The Overlook Crater and lava lake. This crater is larger than a large football stadium.

You can also look at my GoPro timelapse video that I took in 2014 at sunset. I sped this video up 100x.

Below is what our LiDAR setup looks like. The photo shows my two former grad students Adam Lewinter and Amy Burzynski. LiDAR measures 250,000 topographic points a second by bouncing a laser light source off rocks. 

Adam Lewinter and Amy Burzynski, two of my former UNC graduate students, setting up the LiDAR on the edge of Halemaumau crater, looking towards the Overlook Crater.

We can scan the entire Overlook Crater in just a couple of minutes, and can measure rock surfaces more than a kilometer away. We have some new LiDARs that can measure surfaces 6 miles away.  Here is a link for a video put out by the LiDAR manufacturer https://www.youtube.com/watch?v=Tx2dEoUYEf8  - make sure you hit the settings button on the bottom right of the video and chose 1080p to watch in high def!

What did we do: We obtained LiDAR data for 13 different days from 2009 – 2013 and calculated the perimeter of the crater and the volume of rock that fell into the lake between each LiDAR scan.

What did we learn? First, we learned that the perimeter has more than doubled over our study, and the area of the crater gets bigger by ~4000m2 per year, almost exactly the size of the area within a 400 meter running track. Below is a figure of how the perimeter has changed. This allows us to predict how much material will fall into the crater each year, but not how big each rockfall will be or when.

We also could look at the exact shape of the crater, and determine if there were areas that looked unstable and that might pose additional hazards. The movie below is a fly through of Halemaumau and the Overlook crater that shows exactly what the crater looks like. The most important thing is that we found an overhang of about 20 meters. We don’t know if it will all fall into the lake at one time, or if it will break off in many pieces over time, but it is not likely to remain stable.