Earth Sciences and Image Analysis Photographic Highlights

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ISS021-E-5555 Ash and Steam Plume, Soufriere Hills Volcano, Montserrat: The Soufrière Hills, a volcano on the island of Montserrat, in the Lesser Antilles island chain in the Caribbean Sea, has been active since 1995. The most recent eruptive phase of the volcano began with a short swarm of volcano-tectonic earthquakes—earthquakes thought to be caused by movement of magma beneath a volcano—on October 4, 2009, followed by a series of ash-venting events that have continued through October 13, 2009. These venting events create plumes that can deposit ash at significant distances from the volcano. In addition to ash plumes, pyroclastic flows and lava dome growth have been reported as part of the current eruptive activity.
This oblique astronaut photograph from the International Space Station (ISS) captures a white-to-gray ash and steam plume extending westwards from the volcano on October 11, 2009. Oblique images are taken by astronauts looking out from the ISS at an angle, rather than looking straight downward toward the Earth (a perspective called a nadir view), as is common with most remotely sensed data from satellites. An oblique view gives the scene a more three-dimension quality, and provides a look at the vertical structure of the volcanic plume.
While much of the island is covered in green vegetation, gray deposits that include pyroclastic flows and volcanic mudflows (lahars) are visible extending from the volcano toward the coastline. When compared to its extent in earlier views, the volcanic debris has filled in more of the eastern coastline. Urban areas are visible in the northern and western portions of the island; they are recognizable by linear street patterns and the presence of bright building rooftops. The silver-gray appearance of the Caribbean Sea surface is due to sunglint, which is the mirror-like reflection of sunlight off the water surface back towards the handheld camera onboard the ISS. The sunglint highlights surface wave patterns around the island.

ISS021-E-8370 El Misti Volcano and Arequipa, Peru: Several Latin American cities have grown up on the flanks of active volcanoes. This mosaic of two astronaut photographs illustrates the closeness of Arequipa, Peru, to the 5,822-meter- (19,100-foot-) high El Misti Volcano. The symmetric conical shape of El Misti is typical of a stratovolcano, a type of volcano characterized by alternating layers of lava and debris from explosive eruptions, such as ash and pyroclastic flows. Stratovolcanoes are usually located on the continental crust above a subducting tectonic plate. The magma feeding the stratovolcanoes of the Andes Mountains, including El Misti, is associated with ongoing subduction of the Nazca Plate beneath the South American Plate. El Misti’s most recent—and relatively minor—eruption occurred in 1985.
The city center of Arequipa, Peru, lies only 17 kilometers (11 miles) away from the summit of El Misti; the gray urban area is bordered by green agricultural fields (image left). With almost 1 million residents in 2009, it is the second largest city in Peru in terms of population. Much of the building stone for Arequipa, known locally as sillar, is quarried from nearby pyroclastic flow deposits that are white. Arequipa is known as “the White City” because of the prevalence of this building material. The Chili River extends northeastwards from the city center and flows through a canyon (image right) between El Misti volcano and Nevado Chachani to the north. Nevado Chachani is a volcanic complex that may have erupted during the Holocene Epoch (from about 10,000 years ago to the present), but no historical eruptions have been observed there.

ISS021-E-15243 Upsala Glacier, Argentina: The Southern Patagonian Icefield of Argentina and Chile is the southern remnant of the Patagonia Ice Sheet that covered the southern Andes Mountains during the last ice age. This detailed astronaut photograph illustrates the terminus of one of the icefield’s many spectacular glaciers—Upsala Glacier, located on the eastern side of the icefield. Upsala is the third largest glacier in the icefield, and like most other glaciers in the region, it has experienced significant retreat over the past century.
This image was taken during spring in the Southern Hemisphere, and icebergs were calving from the glacier terminus into the waters of Lago Argentino (Lake Argentina, image right). Two icebergs are especially interesting because they retain fragments of the moraine (rock debris) that forms a dark line along the upper surface of the glacier. The inclusion of the moraine illustrates how land-based rocks and sediment may wind up in ocean sediments far from shore.
Moraines are formed from rock and soil debris that accumulate along the front and sides of a flowing glacier. The glacier is like a bulldozer that pushes soil and rock in front of it, leaving debris on either side. When two glaciers merge (image center), moraines along their edges can join to form a medial moraine that is drawn out along the upper surface of the new glacier.
The moraine can be carried intact to the terminus and included in icebergs that then float away, dropping the coarse debris as the iceberg melts. While the icebergs produced by Upsala Glacier do not reach an ocean, many current glaciers do. The existence of ancient glaciers and ice sheets is recorded by layers or pockets of coarse, land-derived sediments within finer-grained sea floor sediments that are located far from any current (or former) coastline.

ISS021-E-11832 Savage Islands, Atlantic Ocean: The Savage Islands, or Ilhas Selvagens in Portuguese, are a small archipelago in the eastern North Atlantic Ocean between the archipelago of Madeira to the north and the Canary Islands to the south. Like these other island groups, the Savage Islands are thought to have been produced by volcanism related to a mantle plume or “hot spot.”
Typically, volcanoes are fueled by magma being generated where tectonic plates are colliding or being pulled apart. The active volcanoes remain at the plate boundaries, even as the plates shift. Mantle plumes, in contrast, are relatively fixed regions of upwelling magma that can feed volcanoes on an overlying tectonic plate. When a tectonic plate passes over the mantle plume, active volcanoes form, but they become dormant as they are carried away from the hot spot on the moving tectonic plate. Over geologic time, this creates a line of older, extinct volcanoes, seamounts, and islands extending from the active volcanoes that are currently over the plume.
These two astronaut photographs illustrate the northern (top) and southern (bottom) Savage Islands. The two views were taken 13 seconds apart from the International Space Station; the geographic center points of the images are separated by about 15 kilometers. Selvagem Grande, with an approximate area of 4 square kilometers, is the largest of the islands. The smaller and more irregularly-shaped Ilhéus do Norte, Ilhéu de Fora, and Selvagem Pequena are visible at the center of the lower image. Spain and Portugal both claim sovereignty over the Savage Islands.
All of the islands of the archipelago are ringed by bright white breaking waves along the fringing beaches. Reefs that surround the Savage Islands make it very difficult to land boats there, and there is no permanent settlement on the islands. The islands serve as nesting sites for several species of seabird including petrels and shearwaters, and they are included on the tentative list of additional UNESCO World Heritage Sites.

ISS021-E-11833 Savage Islands, Atlantic Ocean: The Savage Islands, or Ilhas Selvagens in Portuguese, are a small archipelago in the eastern North Atlantic Ocean between the archipelago of Madeira to the north and the Canary Islands to the south. Like these other island groups, the Savage Islands are thought to have been produced by volcanism related to a mantle plume or “hot spot.”
Typically, volcanoes are fueled by magma being generated where tectonic plates are colliding or being pulled apart. The active volcanoes remain at the plate boundaries, even as the plates shift. Mantle plumes, in contrast, are relatively fixed regions of upwelling magma that can feed volcanoes on an overlying tectonic plate. When a tectonic plate passes over the mantle plume, active volcanoes form, but they become dormant as they are carried away from the hot spot on the moving tectonic plate. Over geologic time, this creates a line of older, extinct volcanoes, seamounts, and islands extending from the active volcanoes that are currently over the plume.
These two astronaut photographs illustrate the northern (top) and southern (bottom) Savage Islands. The two views were taken 13 seconds apart from the International Space Station; the geographic center points of the images are separated by about 15 kilometers. Selvagem Grande, with an approximate area of 4 square kilometers, is the largest of the islands. The smaller and more irregularly-shaped Ilhéus do Norte, Ilhéu de Fora, and Selvagem Pequena are visible at the center of the lower image. Spain and Portugal both claim sovereignty over the Savage Islands.
All of the islands of the archipelago are ringed by bright white breaking waves along the fringing beaches. Reefs that surround the Savage Islands make it very difficult to land boats there, and there is no permanent settlement on the islands. The islands serve as nesting sites for several species of seabird including petrels and shearwaters, and they are included on the tentative list of additional UNESCO World Heritage Sites.

ISS021-E-26475 Ounianga Lakes, Sahara Desert, Chad: This astronaut photograph features one of the largest of a series of ten mostly fresh water lakes in the Ounianga Basin in the heart of the Sahara Desert of northeastern Chad. The lakes are remnants of a single large lake, probably tens of kilometers long, that once occupied this remote area approximately 14,800 to 5,500 years ago. As the climate dried out during the subsequent millennia, the lake shrank, and large, wind-driven sand dunes invaded the original depression, dividing it into several smaller basins.
The area shown in this image is approximately 11 by 9 kilometers. The lakes’ dark surfaces are almost completely segregated by linear, orange sand dunes that stream into the depression from the northeast. The almost-year-round northeast winds and cloudless skies make for very high evaporation rates; an evaporation rate of more than 6 meters per year has been measured in one of the nearby lakes. Despite this, only one of the ten lakes is saline.
The reason for the apparent paradox—fresh water lakes in the heart of the desert—is that fresh water from a very large aquifer reaches the surface in the Ounianga Depression. The aquifer is large enough to keep supplying the small lakes with water despite the high evaporation rate. Mats of floating reeds also reduce the evaporation in places. The lakes form a hydrological system that is unique in the Sahara Desert.
The aquifer was charged with fresh water and the original lake evolved during the African Humid Period (about 14,800 to 5,500 years ago), when the West African summer monsoon was stronger than it is today. Associated southerly winds brought Atlantic moisture well north of modern limits, producing sufficient rainfall in the central Sahara to foster an almost complete savanna vegetation cover.
Pollen data from lake sediments of the original 50-meter-deep Ounianga Lake suggest to scientists that a mild tropical climate and a wooded grassland/savanna ecosystem existed in the region. Ferns grew in the stream floodplains. The same vegetation groups are now only encountered 300 kilometers farther south. Even shrubs that now occur only on the very high, cool summits (above 2,900 meters) of the Tibesti Mountains have been found in the Ounianga Lake sediments.

ISS021-E-15710 Pearl Harbor, Hawaii: This detailed astronaut photograph illustrates the southern coastline of the Hawaiian island Oahu, including Pearl Harbor. On December 7, 1941—68 years ago—a surprise attack by the Japanese Navy on Pearl Harbor and other targets on the island of Oahu precipitated the entry of the United States into World War II. Today, Pearl Harbor is still in use as a major United States Navy installation, and along with Honolulu, it is one of the most heavily developed parts of the island.
A comparison between this image and a 2003 astronaut photograph of Pearl Harbor suggests that little observable land use or land cover change has occurred in the area over the past six years. The most significant difference is the presence of more naval vessels in the Reserve Fleet anchorage in Middle Loch (image center). The urban areas of Waipahu, Pearl City, and Aliamanu border the harbor to the northwest, north, and east. The built-up areas, recognizable by linear streets and white rooftops, contrast sharply with the reddish volcanic soils and green vegetation on the surrounding hills.

ISS021-E-23475 Lake Ilopango, El Salvador: The Central American country of El Salvador occupies a land area nearly the same size as the U.S. State of Massachusetts, and it includes numerous historically active volcanoes. This detailed astronaut photograph highlights the Ilopango Caldera that is located approximately 16 kilometers to the east of the capital city, San Salvador. Calderas are the geologic record of powerful volcanic eruptions that empty out a volcano’s magma chamber; following the eruption, the overlying volcanic structure collapses into the newly formed void, leaving a large crater-like feature (the caldera).
The last caldera-forming eruption at Ilopango occurred during the fifth century AD; it was a powerful event that produced pyroclastic flows that destroyed early Mayan cities in the region. Later volcanic activity included the formation of several lava domes within the lake-filled caldera and near the shoreline. The only historical eruption at Ilopango took place in 1879-80. This activity resulted in the formation of a lava dome in the center of Lake Ilopango. The summit of the dome forms small islets known as Islas Quemadas (visible as small white dots in the larger image). The city of Ilopango borders the lake to the west (image left), while green, vegetated hills ring the rest of the shoreline. White, patchy cumulus clouds are also visible in the image (center and upper left).

STS129-E-6916 Mangroves, Dunes, and Desert on Baja California: Along the west coast of Baja California, roughly one third of the peninsula’s length from its southern tip, the land pokes westward like a slightly bent elbow. The area is a combination of sparsely vegetated desert, sand dunes, mangroves, braided streams, shallow coastal waters, and mountainous islands.
In this astronaut photograph, taken from a vantage point west of the peninsula, north is toward the upper left. Toward the east, the desert appears in shades of tan and beige. Blue-green mangroves infiltrate the desert, following irregular paths toward the northeast. Within these mangroves, deep blue streams and rivers form and flow toward the shallow waters near the coast.
Along the Pacific shore (image lower left), breaking waves form an irregular white line. The waves are barely lighter than the sand dunes of the broad coastal plain, which stretches inland toward the mangroves. West of the mangroves, two islands rise above the ocean surface. Their rugged topography contrasts sharply with that of the thin, curving barrier beach that connects them.
Almost completely surrounded by ocean, the coastal town of Puerto San Carlos serves as a base for tourists visiting the area to watch whales. Grey whale migration season—January through March—brings both cetaceans and tourists to the area.

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This service is provided by the International Space Station program and the JSC Astromaterials Research & Exploration Science Directorate.

Recommended Citation: Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth." .

NASA Responsible Official: Susan Runco

Curator: jsc-earthweb@mail.nasa.gov

Contributors: Earth Sciences Web Team

National Aeronautics and Space Administration

Lyndon B. Johnson Space Center

International Space Station National Laboratory

Last Update:

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ISS021-E-5555	Ash and Steam Plume, Soufriere Hills Volcano, Montserrat: The Soufrière Hills, a volcano on the island of Montserrat, in the Lesser Antilles island chain in the Caribbean Sea, has been active since 1995. The most recent eruptive phase of the volcano began with a short swarm of volcano-tectonic earthquakes—earthquakes thought to be caused by movement of magma beneath a volcano—on October 4, 2009, followed by a series of ash-venting events that have continued through October 13, 2009. These venting events create plumes that can deposit ash at significant distances from the volcano. In addition to ash plumes, pyroclastic flows and lava dome growth have been reported as part of the current eruptive activity. This oblique astronaut photograph from the International Space Station (ISS) captures a white-to-gray ash and steam plume extending westwards from the volcano on October 11, 2009. Oblique images are taken by astronauts looking out from the ISS at an angle, rather than looking straight downward toward the Earth (a perspective called a nadir view), as is common with most remotely sensed data from satellites. An oblique view gives the scene a more three-dimension quality, and provides a look at the vertical structure of the volcanic plume. While much of the island is covered in green vegetation, gray deposits that include pyroclastic flows and volcanic mudflows (lahars) are visible extending from the volcano toward the coastline. When compared to its extent in earlier views, the volcanic debris has filled in more of the eastern coastline. Urban areas are visible in the northern and western portions of the island; they are recognizable by linear street patterns and the presence of bright building rooftops. The silver-gray appearance of the Caribbean Sea surface is due to sunglint, which is the mirror-like reflection of sunlight off the water surface back towards the handheld camera onboard the ISS. The sunglint highlights surface wave patterns around the island.
ISS021-E-8370	El Misti Volcano and Arequipa, Peru: Several Latin American cities have grown up on the flanks of active volcanoes. This mosaic of two astronaut photographs illustrates the closeness of Arequipa, Peru, to the 5,822-meter- (19,100-foot-) high El Misti Volcano. The symmetric conical shape of El Misti is typical of a stratovolcano, a type of volcano characterized by alternating layers of lava and debris from explosive eruptions, such as ash and pyroclastic flows. Stratovolcanoes are usually located on the continental crust above a subducting tectonic plate. The magma feeding the stratovolcanoes of the Andes Mountains, including El Misti, is associated with ongoing subduction of the Nazca Plate beneath the South American Plate. El Misti’s most recent—and relatively minor—eruption occurred in 1985. The city center of Arequipa, Peru, lies only 17 kilometers (11 miles) away from the summit of El Misti; the gray urban area is bordered by green agricultural fields (image left). With almost 1 million residents in 2009, it is the second largest city in Peru in terms of population. Much of the building stone for Arequipa, known locally as sillar, is quarried from nearby pyroclastic flow deposits that are white. Arequipa is known as “the White City” because of the prevalence of this building material. The Chili River extends northeastwards from the city center and flows through a canyon (image right) between El Misti volcano and Nevado Chachani to the north. Nevado Chachani is a volcanic complex that may have erupted during the Holocene Epoch (from about 10,000 years ago to the present), but no historical eruptions have been observed there.
ISS021-E-15243	Upsala Glacier, Argentina: The Southern Patagonian Icefield of Argentina and Chile is the southern remnant of the Patagonia Ice Sheet that covered the southern Andes Mountains during the last ice age. This detailed astronaut photograph illustrates the terminus of one of the icefield’s many spectacular glaciers—Upsala Glacier, located on the eastern side of the icefield. Upsala is the third largest glacier in the icefield, and like most other glaciers in the region, it has experienced significant retreat over the past century. This image was taken during spring in the Southern Hemisphere, and icebergs were calving from the glacier terminus into the waters of Lago Argentino (Lake Argentina, image right). Two icebergs are especially interesting because they retain fragments of the moraine (rock debris) that forms a dark line along the upper surface of the glacier. The inclusion of the moraine illustrates how land-based rocks and sediment may wind up in ocean sediments far from shore. Moraines are formed from rock and soil debris that accumulate along the front and sides of a flowing glacier. The glacier is like a bulldozer that pushes soil and rock in front of it, leaving debris on either side. When two glaciers merge (image center), moraines along their edges can join to form a medial moraine that is drawn out along the upper surface of the new glacier. The moraine can be carried intact to the terminus and included in icebergs that then float away, dropping the coarse debris as the iceberg melts. While the icebergs produced by Upsala Glacier do not reach an ocean, many current glaciers do. The existence of ancient glaciers and ice sheets is recorded by layers or pockets of coarse, land-derived sediments within finer-grained sea floor sediments that are located far from any current (or former) coastline.
ISS021-E-11832	Savage Islands, Atlantic Ocean: The Savage Islands, or Ilhas Selvagens in Portuguese, are a small archipelago in the eastern North Atlantic Ocean between the archipelago of Madeira to the north and the Canary Islands to the south. Like these other island groups, the Savage Islands are thought to have been produced by volcanism related to a mantle plume or “hot spot.” Typically, volcanoes are fueled by magma being generated where tectonic plates are colliding or being pulled apart. The active volcanoes remain at the plate boundaries, even as the plates shift. Mantle plumes, in contrast, are relatively fixed regions of upwelling magma that can feed volcanoes on an overlying tectonic plate. When a tectonic plate passes over the mantle plume, active volcanoes form, but they become dormant as they are carried away from the hot spot on the moving tectonic plate. Over geologic time, this creates a line of older, extinct volcanoes, seamounts, and islands extending from the active volcanoes that are currently over the plume. These two astronaut photographs illustrate the northern (top) and southern (bottom) Savage Islands. The two views were taken 13 seconds apart from the International Space Station; the geographic center points of the images are separated by about 15 kilometers. Selvagem Grande, with an approximate area of 4 square kilometers, is the largest of the islands. The smaller and more irregularly-shaped Ilhéus do Norte, Ilhéu de Fora, and Selvagem Pequena are visible at the center of the lower image. Spain and Portugal both claim sovereignty over the Savage Islands. All of the islands of the archipelago are ringed by bright white breaking waves along the fringing beaches. Reefs that surround the Savage Islands make it very difficult to land boats there, and there is no permanent settlement on the islands. The islands serve as nesting sites for several species of seabird including petrels and shearwaters, and they are included on the tentative list of additional UNESCO World Heritage Sites.
ISS021-E-11833	Savage Islands, Atlantic Ocean: The Savage Islands, or Ilhas Selvagens in Portuguese, are a small archipelago in the eastern North Atlantic Ocean between the archipelago of Madeira to the north and the Canary Islands to the south. Like these other island groups, the Savage Islands are thought to have been produced by volcanism related to a mantle plume or “hot spot.” Typically, volcanoes are fueled by magma being generated where tectonic plates are colliding or being pulled apart. The active volcanoes remain at the plate boundaries, even as the plates shift. Mantle plumes, in contrast, are relatively fixed regions of upwelling magma that can feed volcanoes on an overlying tectonic plate. When a tectonic plate passes over the mantle plume, active volcanoes form, but they become dormant as they are carried away from the hot spot on the moving tectonic plate. Over geologic time, this creates a line of older, extinct volcanoes, seamounts, and islands extending from the active volcanoes that are currently over the plume. These two astronaut photographs illustrate the northern (top) and southern (bottom) Savage Islands. The two views were taken 13 seconds apart from the International Space Station; the geographic center points of the images are separated by about 15 kilometers. Selvagem Grande, with an approximate area of 4 square kilometers, is the largest of the islands. The smaller and more irregularly-shaped Ilhéus do Norte, Ilhéu de Fora, and Selvagem Pequena are visible at the center of the lower image. Spain and Portugal both claim sovereignty over the Savage Islands. All of the islands of the archipelago are ringed by bright white breaking waves along the fringing beaches. Reefs that surround the Savage Islands make it very difficult to land boats there, and there is no permanent settlement on the islands. The islands serve as nesting sites for several species of seabird including petrels and shearwaters, and they are included on the tentative list of additional UNESCO World Heritage Sites.
ISS021-E-26475	Ounianga Lakes, Sahara Desert, Chad: This astronaut photograph features one of the largest of a series of ten mostly fresh water lakes in the Ounianga Basin in the heart of the Sahara Desert of northeastern Chad. The lakes are remnants of a single large lake, probably tens of kilometers long, that once occupied this remote area approximately 14,800 to 5,500 years ago. As the climate dried out during the subsequent millennia, the lake shrank, and large, wind-driven sand dunes invaded the original depression, dividing it into several smaller basins. The area shown in this image is approximately 11 by 9 kilometers. The lakes’ dark surfaces are almost completely segregated by linear, orange sand dunes that stream into the depression from the northeast. The almost-year-round northeast winds and cloudless skies make for very high evaporation rates; an evaporation rate of more than 6 meters per year has been measured in one of the nearby lakes. Despite this, only one of the ten lakes is saline. The reason for the apparent paradox—fresh water lakes in the heart of the desert—is that fresh water from a very large aquifer reaches the surface in the Ounianga Depression. The aquifer is large enough to keep supplying the small lakes with water despite the high evaporation rate. Mats of floating reeds also reduce the evaporation in places. The lakes form a hydrological system that is unique in the Sahara Desert. The aquifer was charged with fresh water and the original lake evolved during the African Humid Period (about 14,800 to 5,500 years ago), when the West African summer monsoon was stronger than it is today. Associated southerly winds brought Atlantic moisture well north of modern limits, producing sufficient rainfall in the central Sahara to foster an almost complete savanna vegetation cover. Pollen data from lake sediments of the original 50-meter-deep Ounianga Lake suggest to scientists that a mild tropical climate and a wooded grassland/savanna ecosystem existed in the region. Ferns grew in the stream floodplains. The same vegetation groups are now only encountered 300 kilometers farther south. Even shrubs that now occur only on the very high, cool summits (above 2,900 meters) of the Tibesti Mountains have been found in the Ounianga Lake sediments.
ISS021-E-15710	Pearl Harbor, Hawaii: This detailed astronaut photograph illustrates the southern coastline of the Hawaiian island Oahu, including Pearl Harbor. On December 7, 1941—68 years ago—a surprise attack by the Japanese Navy on Pearl Harbor and other targets on the island of Oahu precipitated the entry of the United States into World War II. Today, Pearl Harbor is still in use as a major United States Navy installation, and along with Honolulu, it is one of the most heavily developed parts of the island. A comparison between this image and a 2003 astronaut photograph of Pearl Harbor suggests that little observable land use or land cover change has occurred in the area over the past six years. The most significant difference is the presence of more naval vessels in the Reserve Fleet anchorage in Middle Loch (image center). The urban areas of Waipahu, Pearl City, and Aliamanu border the harbor to the northwest, north, and east. The built-up areas, recognizable by linear streets and white rooftops, contrast sharply with the reddish volcanic soils and green vegetation on the surrounding hills.
ISS021-E-23475	Lake Ilopango, El Salvador: The Central American country of El Salvador occupies a land area nearly the same size as the U.S. State of Massachusetts, and it includes numerous historically active volcanoes. This detailed astronaut photograph highlights the Ilopango Caldera that is located approximately 16 kilometers to the east of the capital city, San Salvador. Calderas are the geologic record of powerful volcanic eruptions that empty out a volcano’s magma chamber; following the eruption, the overlying volcanic structure collapses into the newly formed void, leaving a large crater-like feature (the caldera). The last caldera-forming eruption at Ilopango occurred during the fifth century AD; it was a powerful event that produced pyroclastic flows that destroyed early Mayan cities in the region. Later volcanic activity included the formation of several lava domes within the lake-filled caldera and near the shoreline. The only historical eruption at Ilopango took place in 1879-80. This activity resulted in the formation of a lava dome in the center of Lake Ilopango. The summit of the dome forms small islets known as Islas Quemadas (visible as small white dots in the larger image). The city of Ilopango borders the lake to the west (image left), while green, vegetated hills ring the rest of the shoreline. White, patchy cumulus clouds are also visible in the image (center and upper left).
STS129-E-6916	Mangroves, Dunes, and Desert on Baja California: Along the west coast of Baja California, roughly one third of the peninsula’s length from its southern tip, the land pokes westward like a slightly bent elbow. The area is a combination of sparsely vegetated desert, sand dunes, mangroves, braided streams, shallow coastal waters, and mountainous islands. In this astronaut photograph, taken from a vantage point west of the peninsula, north is toward the upper left. Toward the east, the desert appears in shades of tan and beige. Blue-green mangroves infiltrate the desert, following irregular paths toward the northeast. Within these mangroves, deep blue streams and rivers form and flow toward the shallow waters near the coast. Along the Pacific shore (image lower left), breaking waves form an irregular white line. The waves are barely lighter than the sand dunes of the broad coastal plain, which stretches inland toward the mangroves. West of the mangroves, two islands rise above the ocean surface. Their rugged topography contrasts sharply with that of the thin, curving barrier beach that connects them. Almost completely surrounded by ocean, the coastal town of Puerto San Carlos serves as a base for tourists visiting the area to watch whales. Grey whale migration season—January through March—brings both cetaceans and tourists to the area.

This service is provided by the International Space Station program and the JSC Astromaterials Research & Exploration Science Directorate. Recommended Citation: Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth." .
	NASA Responsible Official: Susan Runco Curator: jsc-earthweb@mail.nasa.gov Contributors: Earth Sciences Web Team	National Aeronautics and Space Administration Lyndon B. Johnson Space Center	International Space Station National Laboratory Last Update:
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