Images

Detail of levee on an active channelized aa flow. Note the pahoehoe overflows in the levees and the level of the active flow below the tops of the levees. This lower flow level is not allowed in the commonly used "Bingham" model of lava flows.

Detail of levee on an active channelized aa flow. Note the pahoehoe overflows in the levees and the level of the active flow below the tops of the levees. This lower flow level is not allowed in the commonly used "Bingham" model of lava flows.

A section of burst tumulus that has fallen away from the larger structure. Tumuli can burst when the influx of lava is rapid compared to the rate at which the crust is thickening by cooling. In these cases the pressure driving the lava is significantly greater than the weight of the overlying crust.

An a'a' channel near the Royal Gardens subdivision on Kilauea Volcano, Hawaii. The flows in the background are from the 1980s. Note that the flow level is below the levees and the pahoehoe overflows emplaced on top of the a'a'. 

Pu’u ‘Ō’ō is a cinder and spatter cone in Kilauea’s east rift zone. It began erupting on January 3, 1983; a summary of its eruption can be found here. This image shows the result of the largest of the collapse pits that began to appear around 1993.

Burned-out buildings in downtown Grand Forks, North Dakota.

Flooding of homes in Grand Forks, North Dakota in 1997.

An inundated building in Grand Forks, North Dakota durring the Red River of the North Flood.

Boats on city streets of Grand Forks, North Dakota and East Grand Forks, Minnesota during the 1997 Red River of the North flood.

The Holiday Mall in East Grand Forks, Minnesota, during the Red River of the North flood.

Downtown Grand Forks, North Dakota flooded by the Red River of the North in 1997.

Grand Forks flooding on Highway 2.

The Sorlie Bridge between Grand Forks, North Dakota and East Grand Forks, Minnesota, during the 1997 Red River of the North flood.

U.S. Geological Survey employees being transported to sites by National Guard personnel.

Fire consumes an building on a farmstead near the Red River of the North in northeastern North Dakota.

Flood waters inundated Grand Forks, North Dakota and East Grand Forks, Minnesota.The picture is looking west to Grand Forks, North Dakota and the  USGS gage house is the small white square in the center of the picture.

The flag of the United States of American flies over flood water in Grand Forks, North Dakota.

Photograph of the large jökulhlaup that spread out across Skeiðarársandur (glacial outwash plain) from the terminus of Skeiðarárjökull, an outlet glacier of Vatnajökull.

A crystallized dacite flow in northern Chile. Dacite is extrusive and the volcanic equivalent of granodiorite. 

Channelized flows on Socompa. Socompa is a large stratovolcano on the border between Chile and Argentina, the youngest of a chain of volcanoes that runs northeast to southwest.

A burst tumulus near Kamokuna, which is a lava delta where Puʻu ʻŌʻō flows enter the Pacific Ocean. Tumuli can burst when the influx of lava is rapid compared to the rate at which the crust is thickening by cooling. In these cases the pressure driving the lava is significantly greater than the weight of the overlying crust.