The Big Island of Hawaii is continuously shaped by active volcanic eruptions, primarily from Kilauea and Mauna Loa. The constant flow of lava into the ocean perpetually reforms and expands the island’s coastline.
Understanding Land Growth Estimates
The Big Island of Hawaii continues to grow due to persistent volcanic activity. The amount of new land added each year is not a fixed measurement, but rather a variable estimate dependent on the intensity and duration of eruptions.
For instance, the 2018 Kilauea eruption alone added approximately 875 acres. Historically, continuous lava flows from the Puʻu ʻŌʻō vent (1983-2018) contributed around 570 acres. From November 1986 through December 2009, Kilauea formed about 475 acres. While some estimates suggest an average of 32 acres annually, these figures underscore the episodic and substantial nature of land creation during major eruptive phases.
The Process of Volcanic Land Formation
New land on the Big Island forms when molten rock erupts from volcanoes and flows downslope, reaching the Pacific Ocean. As this hot lava comes into contact with seawater, it cools rapidly and solidifies, building up new rock formations. This process often creates deltas that extend the island’s shoreline.
Hawaiian volcanoes primarily erupt basaltic lava, known for its fluidity. Two main forms of lava flows are observed: pāhoehoe and ‘a‘ā.
Pāhoehoe flows have smooth, billowy, or ropy surfaces, forming from less viscous lava that moves slowly. In contrast, ‘a‘ā flows have rough, jagged, or clinkery surfaces, developing when lava is more viscous or flows rapidly, causing its surface to tear apart. Both types contribute to land accretion; pāhoehoe sometimes forms insulating lava tubes, allowing lava to travel far beneath a solidified crust.
Tracking New Land from Above
Scientists employ various methods to monitor and calculate new land created by volcanic eruptions. The U.S. Geological Survey’s Hawaiian Volcano Observatory (USGS HVO) plays a significant role in this ongoing observation.
They utilize satellite imagery, such as NASA’s Earth Observing-1 data, to track lava flows as they advance and interact with the ocean. Aerial photography, often captured by unmanned aerial vehicles (UAVs) and helicopters, provides detailed visual records of the changing landscape.
Advanced techniques like Light Detection and Ranging (LiDAR) generate precise three-dimensional digital elevation models (DEMs), allowing scientists to calculate the volume of new lava. Global Positioning System (GPS) mapping and other precise surveying methods help track ground deformation and delineate newly formed coastlines.
Characteristics of New Volcanic Terrain
New land on the Big Island initially presents as a stark, barren landscape. This terrain consists primarily of volcanic rock, specifically basalt, which appears rugged and unyielding. Its immediate nature makes it unsuitable for human development or agricultural use.
Despite its harsh appearance, this new land begins ecological succession. Pioneer species, such as lichens, mosses, and hardy ferns, are among the first to colonize the barren rock. These organisms establish themselves in small cracks and depressions where organic material, seeds, and spores can accumulate.
Over time, their presence contributes to the breakdown of volcanic rock and the gradual formation of thin soil layers. The speed of this natural development varies, with wetter, windward areas supporting faster ecological changes compared to drier regions.