Images

Emergency response planning exercise for a volcanic event with Washington State and local government officials.

Top: Photograph of the SO2 camera installation when scientists tested the radio link to the Hawaiian Volcano Observatory (HVO). The camera is aimed at the plume emitting from the Overlook Crater, about 1.4 km away. Under typical trade wind conditions, the plume is blown to the southwest, thus moving from right to left in the imagery.

Vent activity, typical of that in summer and fall 1969 between episodes of high fountaining. The spattering is from one of two compartments that contained lava. Typically lava levels in the two compartments were different, and gas pistons might work in both but at different times.

Map showing area covered by lava flows of Mauna Ulu eruption. Note that the map was made in 1997, before diacritical marks were being used in Hawaiian place names. The two colors designate the 1969-71 and 1972-1974 parts of the eruption, respectively. In the scale, 3 km is equal to about 2 mi.

Haleakalā Volcano map showing strata of the HANA Volcanics by age.

Distribution of young volcanic rocks by age in Haleakalā Crater, Maui.

CalVO geologists Duane Champion and Drew Downs collect paleomagnetic samples from basalt lava flows at Eagle Lake

Aerial view of Haleakalā Crater northward to Ko‘olau Gap. Sharp rimmed crater in near ground is Ka Lu‘u o ka ‘Ō‘ō.

Vectors indicate Pacific Plate motion relative to presumed fixed mantle hot spot in millimeters per year. Gray lines indicate fracture zones. Isochrons along the Emperor Seamounts chain show the age of volcanism in millions of years. Ocean floor ages from imagery available on EarthByte.

Drill records have found traces of previously formed shorelines (strandlines) depressed below the current sea level - further evidence of subsidence due to the added weight of the volcano.

Postshield eruption are the fourth stage of a Hawaiian volcano's evolution. A cap of evolved magma erupts to cover the surface of the volcano. Not all volcanoes have evidence for this phase.

Rejuvenated stage volcanism occurs after the volcano has moved away from the mantle hot spot. Eruptions occur in sporadic locations and may be interspersed with long periods of erosion.

Seismic hazard across the State of Hawaii, with high seismic hazards depicted with warm colors (red-orange) and relatively low seismic hazards depicted with cool colors (green). Engineers use these types of maps to prescribe building codes known as Seismic Design Codes (SDC) and create earthquake resistant structures.

Seismic station locations (red triangles) on the Island of Hawai‘i and across the State of Hawaii (inset).

HVO seismologists use this to review automatically generated earthquake parameters (location, depth, magnitude), measure P- and S-wave arrival times, and re-compute earthquake hypocenter and magnitudes for cataloging and distribution to the public.

Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.

Earthquakes near the Island of Hawai‘i between 1970-2006 with magnitude greater than 2.5. A (top left): locations of shallow earthquakes 0-22 km (0-14 mi) depth. B (top right): locations of deep earthquakes 22-55 km depth (14-34 mi). Bottom (C): cross section showing the depths of earthquakes in the rectangle in figure B.

Examples of seismograms of different types of earthquakes and tremor (constant ground shaking) recorded in Hawai‘i.

Moderate ash on corn crops from eruption of Tungurahua, Ecuador, 2007.

Geologic Map of Three Sisters Volcanic Cluster, Cascade Range, Oregon

Brimstone Basin, Yellowstone, aerial photo with overlay of two types of altered ground (light blue and pale pink shading) and locations of gas measurements (red dots). 2012 study