GPS solution provides 3-minute tsunami alerts

Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset. For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of the European Geosciences Union (EGU).

Most tsunamis, including those in offshore Sumatra, Indonesia in 2004 and Japan in 2011, occur following underwater ground motion in subduction zones, locations where a tectonic plate slips under another causing a large earthquake. To a lesser extent, the resulting uplift of the sea floor also affects coastal regions. There, researchers can measure the small ground deformation along the coast with GPS and use this to determine tsunami information.

“High-precision real-time processing and inversion of these data enable reconstruction of the earthquake source, described as slip at the subduction interface. This can be used to calculate the uplift of the sea floor, which in turn is used as initial condition for a tsunami model to predict arrival times and maximum wave heights at the coast,” says lead-author Andreas Hoechner from the German Research Centre for Geosciences (GFZ).

In the new Natural Hazards and Earth System Sciences paper, the researchers use the Japan 2011 tsunami, which hit the country’s northeast coast in less than half an hour and caused significant damage, as a case study. They show that their method could have provided detailed tsunami alert as soon as three minutes after the beginning of the earthquake that generated it.

“Japan has a very dense network of GPS stations, but these were not being used for tsunami early warning as of 2011. Certainly this is going to change soon,” states Hoechner.

The scientists used raw data from the Japanese GPS Earth Observation Network (GEONET) recorded a day before to a day after the 2011 earthquake. To shorten the time needed to provide a tsunami alert, they only used data from 50 GPS stations on the northeast coast of Japan, out of about 1200 GEONET stations available in the country.

At present, tsunami warning is based on seismological methods. However, within the time limit of 5 to 10 minutes, these traditional techniques tend to underestimate the earthquake magnitude of large events. Furthermore, they provide only limited information on the geometry of the tsunami source (see note). Both factors can lead to underprediction of wave heights and tsunami coastal impact. Hoechner and his team say their method does not suffer from the same problems and can provide fast, detailed and accurate tsunami alerts.

The next step is to see how the GPS solution works in practice in Japan or other areas prone to devastating tsunamis. As part of the GFZ-lead German Indonesian Tsunami Early Warning System project, several GPS stations were installed in Indonesia after the 2004 earthquake and tsunami near Sumatra, and are already providing valuable information for the warning system.

“The station density is not yet high enough for an independent tsunami early warning in Indonesia, since it is a requirement for this method that the stations be placed densely close to the area of possible earthquake sources, but more stations are being added,” says Hoechner.

GPS solution provides 3-minute tsunami alerts

Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset. For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of the European Geosciences Union (EGU).

Most tsunamis, including those in offshore Sumatra, Indonesia in 2004 and Japan in 2011, occur following underwater ground motion in subduction zones, locations where a tectonic plate slips under another causing a large earthquake. To a lesser extent, the resulting uplift of the sea floor also affects coastal regions. There, researchers can measure the small ground deformation along the coast with GPS and use this to determine tsunami information.

“High-precision real-time processing and inversion of these data enable reconstruction of the earthquake source, described as slip at the subduction interface. This can be used to calculate the uplift of the sea floor, which in turn is used as initial condition for a tsunami model to predict arrival times and maximum wave heights at the coast,” says lead-author Andreas Hoechner from the German Research Centre for Geosciences (GFZ).

In the new Natural Hazards and Earth System Sciences paper, the researchers use the Japan 2011 tsunami, which hit the country’s northeast coast in less than half an hour and caused significant damage, as a case study. They show that their method could have provided detailed tsunami alert as soon as three minutes after the beginning of the earthquake that generated it.

“Japan has a very dense network of GPS stations, but these were not being used for tsunami early warning as of 2011. Certainly this is going to change soon,” states Hoechner.

The scientists used raw data from the Japanese GPS Earth Observation Network (GEONET) recorded a day before to a day after the 2011 earthquake. To shorten the time needed to provide a tsunami alert, they only used data from 50 GPS stations on the northeast coast of Japan, out of about 1200 GEONET stations available in the country.

At present, tsunami warning is based on seismological methods. However, within the time limit of 5 to 10 minutes, these traditional techniques tend to underestimate the earthquake magnitude of large events. Furthermore, they provide only limited information on the geometry of the tsunami source (see note). Both factors can lead to underprediction of wave heights and tsunami coastal impact. Hoechner and his team say their method does not suffer from the same problems and can provide fast, detailed and accurate tsunami alerts.

The next step is to see how the GPS solution works in practice in Japan or other areas prone to devastating tsunamis. As part of the GFZ-lead German Indonesian Tsunami Early Warning System project, several GPS stations were installed in Indonesia after the 2004 earthquake and tsunami near Sumatra, and are already providing valuable information for the warning system.

“The station density is not yet high enough for an independent tsunami early warning in Indonesia, since it is a requirement for this method that the stations be placed densely close to the area of possible earthquake sources, but more stations are being added,” says Hoechner.

Rio Grande rift: From tectonics to groundwater, north to south

This is the cover of GSA Special Paper 494: New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater. -  Mark R. Hudson and V.J.S. (Tien) Grauch (editors)
This is the cover of GSA Special Paper 494: New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater. – Mark R. Hudson and V.J.S. (Tien) Grauch (editors)

Extending from Colorado, USA, to the state of Chihuahua, Mexico, the Rio Grande rift divides the Colorado Plateau on the west from the interior of the North American craton on the east. The rift is named after the Rio Grande, the major river that flows through most of its extent, from southern Colorado, through New Mexico, and along the border between Texas, USA, and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas.

Individual valleys of the Rio Grande rift are easy to recognize to the north, but more difficult in the Basin and Range in southern New Mexico, west Texas, and northern Mexico. This new book from The Geological Society of America focuses on the Rio Grande rift’s upper crustal basins.

Editors Mark R. Hudson and V.J.S. (Tien) Grauch of the U.S. Geological Survey have organized the book geographically, with study areas progressing from north to south. Eighteen chapters cover a variety of topics, including sedimentation history, rift basin geometries and the influence of older structure on rift basin evolution, faulting and strain transfer within and among basins, relations of magmatism to rift tectonism, and basin hydrogeology.

Western Indian Ocean earthquake and tsunami hazard potential greater than previously thought

The location of the Makran subduction zone of Pakistan and Iran and locations of recorded earthquakes including the 1945 magnitude 8.1 earthquake (red dot to the north indicates the 1947 magnitude 7.3 earthquake). The profile for the thermal modelling of this study is the N-S trending black line, with distance given along the profile from the shallowest part of the subduction zone in the south (0 kilometers) to the most northern potential earthquake rupture extent (350 kilometers). -  University of Southampton Ocean and Earth Science
The location of the Makran subduction zone of Pakistan and Iran and locations of recorded earthquakes including the 1945 magnitude 8.1 earthquake (red dot to the north indicates the 1947 magnitude 7.3 earthquake). The profile for the thermal modelling of this study is the N-S trending black line, with distance given along the profile from the shallowest part of the subduction zone in the south (0 kilometers) to the most northern potential earthquake rupture extent (350 kilometers). – University of Southampton Ocean and Earth Science

Earthquakes similar in magnitude to the 2004 Sumatra earthquake could occur in an area beneath the Arabian Sea at the Makran subduction zone, according to recent research published in Geophysical Research Letters.

The research was carried out by scientists from the University of Southampton based at the National Oceanography Centre Southampton (NOCS), and the Pacific Geoscience Centre, Natural Resources Canada.

The study suggests that the risk from undersea earthquakes and associated tsunami in this area of the Western Indian Ocean – which could threaten the coastlines of Pakistan, Iran, Oman, India and potentially further afield – has been previously underestimated. The results highlight the need for further investigation of pre-historic earthquakes and should be fed into hazard assessment and planning for the region.

Subduction zones are areas where two of the Earth’s tectonic plates collide and one is pushed beneath the other. When an earthquake occurs here, the seabed moves horizontally and vertically as the pressure is released, displacing large volumes of water that can result in a tsunami.

The Makran subduction zone has shown little earthquake activity since a magnitude 8.1 earthquake in 1945 and magnitude 7.3 in 1947. Because of its relatively low seismicity and limited recorded historic earthquakes it has often been considered incapable of generating major earthquakes.

Plate boundary faults at subduction zones are expected to be prone to rupture generating earthquakes at temperatures of between 150 and 450 °C. The scientists used this relationship to map out the area of the potential fault rupture zone beneath the Makran by calculating the temperatures where the plates meet. Larger fault rupture zones result in larger magnitude earthquakes.

“Thermal modelling suggests that the potential earthquake rupture zone extends a long way northward, to a width of up to 350 kilometres which is unusually wide relative to most other subduction zones,” says Gemma Smith, lead author and PhD student at University of Southampton School of Ocean and Earth Science, which is based at NOCS.

The team also found that the thickness of the sediment on the subducting plate could be a contributing factor to the magnitude of an earthquake and tsunami there.

“If the sediments between the plates are too weak then they might not be strong enough to allow the strain between the two plates to build up,” says Smith. “But here we see much thicker sediments than usual, which means the deeper sediments will be more compressed and warmer. The heat and pressure make the sediments stronger. This results in the shallowest part of the subduction zone fault being potentially capable of slipping during an earthquake.

“These combined factors mean the Makran subduction zone is potentially capable of producing major earthquakes, up to magnitude 8.7-9.2. Past assumptions may have significantly underestimated the earthquake and tsunami hazard in this region.”

Rio Grande rift: From tectonics to groundwater, north to south

This is the cover of GSA Special Paper 494: New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater. -  Mark R. Hudson and V.J.S. (Tien) Grauch (editors)
This is the cover of GSA Special Paper 494: New Perspectives on Rio Grande Rift Basins: From Tectonics to Groundwater. – Mark R. Hudson and V.J.S. (Tien) Grauch (editors)

Extending from Colorado, USA, to the state of Chihuahua, Mexico, the Rio Grande rift divides the Colorado Plateau on the west from the interior of the North American craton on the east. The rift is named after the Rio Grande, the major river that flows through most of its extent, from southern Colorado, through New Mexico, and along the border between Texas, USA, and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas.

Individual valleys of the Rio Grande rift are easy to recognize to the north, but more difficult in the Basin and Range in southern New Mexico, west Texas, and northern Mexico. This new book from The Geological Society of America focuses on the Rio Grande rift’s upper crustal basins.

Editors Mark R. Hudson and V.J.S. (Tien) Grauch of the U.S. Geological Survey have organized the book geographically, with study areas progressing from north to south. Eighteen chapters cover a variety of topics, including sedimentation history, rift basin geometries and the influence of older structure on rift basin evolution, faulting and strain transfer within and among basins, relations of magmatism to rift tectonism, and basin hydrogeology.

Western Indian Ocean earthquake and tsunami hazard potential greater than previously thought

The location of the Makran subduction zone of Pakistan and Iran and locations of recorded earthquakes including the 1945 magnitude 8.1 earthquake (red dot to the north indicates the 1947 magnitude 7.3 earthquake). The profile for the thermal modelling of this study is the N-S trending black line, with distance given along the profile from the shallowest part of the subduction zone in the south (0 kilometers) to the most northern potential earthquake rupture extent (350 kilometers). -  University of Southampton Ocean and Earth Science
The location of the Makran subduction zone of Pakistan and Iran and locations of recorded earthquakes including the 1945 magnitude 8.1 earthquake (red dot to the north indicates the 1947 magnitude 7.3 earthquake). The profile for the thermal modelling of this study is the N-S trending black line, with distance given along the profile from the shallowest part of the subduction zone in the south (0 kilometers) to the most northern potential earthquake rupture extent (350 kilometers). – University of Southampton Ocean and Earth Science

Earthquakes similar in magnitude to the 2004 Sumatra earthquake could occur in an area beneath the Arabian Sea at the Makran subduction zone, according to recent research published in Geophysical Research Letters.

The research was carried out by scientists from the University of Southampton based at the National Oceanography Centre Southampton (NOCS), and the Pacific Geoscience Centre, Natural Resources Canada.

The study suggests that the risk from undersea earthquakes and associated tsunami in this area of the Western Indian Ocean – which could threaten the coastlines of Pakistan, Iran, Oman, India and potentially further afield – has been previously underestimated. The results highlight the need for further investigation of pre-historic earthquakes and should be fed into hazard assessment and planning for the region.

Subduction zones are areas where two of the Earth’s tectonic plates collide and one is pushed beneath the other. When an earthquake occurs here, the seabed moves horizontally and vertically as the pressure is released, displacing large volumes of water that can result in a tsunami.

The Makran subduction zone has shown little earthquake activity since a magnitude 8.1 earthquake in 1945 and magnitude 7.3 in 1947. Because of its relatively low seismicity and limited recorded historic earthquakes it has often been considered incapable of generating major earthquakes.

Plate boundary faults at subduction zones are expected to be prone to rupture generating earthquakes at temperatures of between 150 and 450 °C. The scientists used this relationship to map out the area of the potential fault rupture zone beneath the Makran by calculating the temperatures where the plates meet. Larger fault rupture zones result in larger magnitude earthquakes.

“Thermal modelling suggests that the potential earthquake rupture zone extends a long way northward, to a width of up to 350 kilometres which is unusually wide relative to most other subduction zones,” says Gemma Smith, lead author and PhD student at University of Southampton School of Ocean and Earth Science, which is based at NOCS.

The team also found that the thickness of the sediment on the subducting plate could be a contributing factor to the magnitude of an earthquake and tsunami there.

“If the sediments between the plates are too weak then they might not be strong enough to allow the strain between the two plates to build up,” says Smith. “But here we see much thicker sediments than usual, which means the deeper sediments will be more compressed and warmer. The heat and pressure make the sediments stronger. This results in the shallowest part of the subduction zone fault being potentially capable of slipping during an earthquake.

“These combined factors mean the Makran subduction zone is potentially capable of producing major earthquakes, up to magnitude 8.7-9.2. Past assumptions may have significantly underestimated the earthquake and tsunami hazard in this region.”

Research helps paint finer picture of massive 1700 earthquake

In 1700, a massive earthquake struck the west coast of North America. Though it was powerful enough to cause a tsunami as far as Japan, a lack of local documentation has made studying this historic event challenging.

Now, researchers from the University of Pennsylvania have helped unlock this geological mystery using a fossil-based technique. Their work provides a finer-grained portrait of this earthquake and the changes in coastal land level it produced, enabling modelers to better prepare for future events.

Penn’s team includes Benjamin Horton, associate professor and director of the Sea Level Research Laboratory in the Department of Earth and Environmental Science in the School of Arts and Sciences, along with then lab members Simon Engelhart and Andrea Hawkes. They collaborated with researchers from Canada’s University of Victoria, the National Taiwan University, the Geological Survey of Canada and the United States Geological Survey.

The research was published in the Journal of Geophysical Research: Solid Earth.

The Cascadia Subduction Zone runs along the Pacific Northwest coast of the United States to Vancouver Island in Canada. This major fault line is capable of producing megathrust earthquakes 9.0 or higher, though, due to a dearth of observations or historical records, this trait was only discovered within the last several decades from geology records. The Lewis and Clark expedition did not make the first extensive surveys of the region until more than 100 years later, and contemporaneous aboriginal accounts were scarce and incomplete.

The 1700 Cascadia event was better documented in Japan than in the Americas. Records of the “orphan tsunami” – so named because its “parent” earthquake was too far away to be felt – gave earth scientists hints that this subduction zone was capable of such massive seismic activity. Geological studies provided information about the earthquake, but many critical details remained lost to history.

“Previous research had determined the timing and the magnitude, but what we didn’t know was how the rupture happened,” Horton said. “Did it rupture in one big long segment, more than a thousand kilometers, or did it rupture in parcels?”

To provide a clearer picture of how the earthquake occurred, Horton and his colleagues applied a technique they have used in assessing historic sea-level rise. They traveled to various sites along the Cascadia subduction zone, taking core samples from up and down the coast and working with local researchers who donated pre-existing data sets. The researchers’ targets were microscopic fossils known as foraminifera. Through radiocarbon dating and an analysis of different species’ positions with the cores over time, the researchers were able to piece together a historical picture of the changes in land and sea level along the coastline. The research revealed how much the coast suddenly subsided during the earthquake. This subsidence was used to infer how much the tectonic plates moved during the earthquake.

“What we were able to show for the first time is that the rupture of Cascadia was heterogeneous, making it similar to what happened with the recent major earthquakes in Japan, Chile and Sumatra,” Horton said.

This level of regional detail for land level changes is critical for modeling and disaster planning.

“It’s only when you have that data that you can start to build accurate models of earthquake ruptures and tsunami inundation,” Horton said. “There were areas of the west coast of the United States that were more susceptible to larger coastal subsidence than others.”

The Cascadia subduction zone is of particular interest to geologists and coastal managers because geological evidence points to recurring seismic activity along the fault line, with intervals between 300 and 500 years. With the last major event occurring in 1700, another earthquake could be on the horizon. A better understanding of how such an event might unfold has the potential to save lives.

“The next Cascadia earthquake has the potential to be the biggest natural disaster that the Unites States will have to come to terms with – far bigger than Sandy or even Katrina,” Horton said. “It would happen with very little warning; some areas of Oregon will have less than 20 minutes to evacuate before a large tsunami will inundate the coastline like in Sumatra in 2004 and Japan in 2011.”

Research helps paint finer picture of massive 1700 earthquake

In 1700, a massive earthquake struck the west coast of North America. Though it was powerful enough to cause a tsunami as far as Japan, a lack of local documentation has made studying this historic event challenging.

Now, researchers from the University of Pennsylvania have helped unlock this geological mystery using a fossil-based technique. Their work provides a finer-grained portrait of this earthquake and the changes in coastal land level it produced, enabling modelers to better prepare for future events.

Penn’s team includes Benjamin Horton, associate professor and director of the Sea Level Research Laboratory in the Department of Earth and Environmental Science in the School of Arts and Sciences, along with then lab members Simon Engelhart and Andrea Hawkes. They collaborated with researchers from Canada’s University of Victoria, the National Taiwan University, the Geological Survey of Canada and the United States Geological Survey.

The research was published in the Journal of Geophysical Research: Solid Earth.

The Cascadia Subduction Zone runs along the Pacific Northwest coast of the United States to Vancouver Island in Canada. This major fault line is capable of producing megathrust earthquakes 9.0 or higher, though, due to a dearth of observations or historical records, this trait was only discovered within the last several decades from geology records. The Lewis and Clark expedition did not make the first extensive surveys of the region until more than 100 years later, and contemporaneous aboriginal accounts were scarce and incomplete.

The 1700 Cascadia event was better documented in Japan than in the Americas. Records of the “orphan tsunami” – so named because its “parent” earthquake was too far away to be felt – gave earth scientists hints that this subduction zone was capable of such massive seismic activity. Geological studies provided information about the earthquake, but many critical details remained lost to history.

“Previous research had determined the timing and the magnitude, but what we didn’t know was how the rupture happened,” Horton said. “Did it rupture in one big long segment, more than a thousand kilometers, or did it rupture in parcels?”

To provide a clearer picture of how the earthquake occurred, Horton and his colleagues applied a technique they have used in assessing historic sea-level rise. They traveled to various sites along the Cascadia subduction zone, taking core samples from up and down the coast and working with local researchers who donated pre-existing data sets. The researchers’ targets were microscopic fossils known as foraminifera. Through radiocarbon dating and an analysis of different species’ positions with the cores over time, the researchers were able to piece together a historical picture of the changes in land and sea level along the coastline. The research revealed how much the coast suddenly subsided during the earthquake. This subsidence was used to infer how much the tectonic plates moved during the earthquake.

“What we were able to show for the first time is that the rupture of Cascadia was heterogeneous, making it similar to what happened with the recent major earthquakes in Japan, Chile and Sumatra,” Horton said.

This level of regional detail for land level changes is critical for modeling and disaster planning.

“It’s only when you have that data that you can start to build accurate models of earthquake ruptures and tsunami inundation,” Horton said. “There were areas of the west coast of the United States that were more susceptible to larger coastal subsidence than others.”

The Cascadia subduction zone is of particular interest to geologists and coastal managers because geological evidence points to recurring seismic activity along the fault line, with intervals between 300 and 500 years. With the last major event occurring in 1700, another earthquake could be on the horizon. A better understanding of how such an event might unfold has the potential to save lives.

“The next Cascadia earthquake has the potential to be the biggest natural disaster that the Unites States will have to come to terms with – far bigger than Sandy or even Katrina,” Horton said. “It would happen with very little warning; some areas of Oregon will have less than 20 minutes to evacuate before a large tsunami will inundate the coastline like in Sumatra in 2004 and Japan in 2011.”

Scientists find extensive glacial retreat in Mount Everest region

Researchers taking a new look at the snow and ice covering Mount Everest and the national park that surrounds it are finding abundant evidence that the world’s tallest peak is shedding its frozen cloak. The scientists have also been studying temperature and precipitation trends in the area and
found that the Everest region has been warming while snowfall has been declining since the early 1990s.

Members of the team conducting these studies will present their
findings on May 14 at the Meeting of the Americas in Cancun,
Mexico – a scientific conference organized and co-sponsored by
the American Geophysical Union.

Glaciers in the Mount Everest region have shrunk by 13 percent
in the last 50 years and the snowline has shifted upward by 180
meters (590 feet), according to Sudeep Thakuri, who is leading
the research as part of his PhD graduate studies at the University
of Milan in Italy.

Glaciers smaller than one square kilometer are
disappearing the fastest and have experienced a 43 percent
decrease in surface area since the 1960s. Because the glaciers are
melting faster than they are replenished by ice and snow, they are
revealing rocks and debris that were previously hidden deep
under the ice. These debris-covered sections of the glaciers have
increased by about 17 percent since the 1960s, according to
Thakuri. The ends of the glaciers have also retreated by an
average of 400 meters since 1962, his team found.

The researchers suspect that the decline of snow and ice in the
Everest region is from human-generated greenhouse gases
altering global climate. However, they have not yet established a
firm connection between the mountains’ changes and climate
change, Thakuri said.

He and his team determined the extent of glacial change on
Everest and the surrounding 1,148 square kilometer (713 square
mile) Sagarmatha National Park by compiling satellite imagery
and topographic maps and reconstructing the glacial history.
Their statistical analysis shows that the majority of the glaciers in
the national park are retreating at an increasing rate, Thakuri
said.

To evaluate the temperature and precipitation patterns in the
area, Thakuri and his colleagues have been analyzing hydro-
meteorological data from the Nepal Climate Observatory stations
and Nepal’s Department of Hydrology and Meteorology. The
researchers found that the Everest region has undergone a 0.6
degree Celsius (1.08 degrees Fahrenheit) increase in temperature
and 100 millimeter (3.9 inches) decrease in precipitation during
the pre-monsoon and winter months since 1992.

In subsequent research, Thakuri plans on exploring the climate-
glacier relationship further with the aim of integrating the
glaciological, hydrological and climatic data to understand the
behavior of the hydrological cycle and future water availability.

“The Himalayan glaciers and ice caps are considered a water
tower for Asia since they store and supply water downstream
during the dry season,” said Thakuri. “Downstream populations
are dependent on the melt water for agriculture, drinking, and
power production.”

Scientists find extensive glacial retreat in Mount Everest region

Researchers taking a new look at the snow and ice covering Mount Everest and the national park that surrounds it are finding abundant evidence that the world’s tallest peak is shedding its frozen cloak. The scientists have also been studying temperature and precipitation trends in the area and
found that the Everest region has been warming while snowfall has been declining since the early 1990s.

Members of the team conducting these studies will present their
findings on May 14 at the Meeting of the Americas in Cancun,
Mexico – a scientific conference organized and co-sponsored by
the American Geophysical Union.

Glaciers in the Mount Everest region have shrunk by 13 percent
in the last 50 years and the snowline has shifted upward by 180
meters (590 feet), according to Sudeep Thakuri, who is leading
the research as part of his PhD graduate studies at the University
of Milan in Italy.

Glaciers smaller than one square kilometer are
disappearing the fastest and have experienced a 43 percent
decrease in surface area since the 1960s. Because the glaciers are
melting faster than they are replenished by ice and snow, they are
revealing rocks and debris that were previously hidden deep
under the ice. These debris-covered sections of the glaciers have
increased by about 17 percent since the 1960s, according to
Thakuri. The ends of the glaciers have also retreated by an
average of 400 meters since 1962, his team found.

The researchers suspect that the decline of snow and ice in the
Everest region is from human-generated greenhouse gases
altering global climate. However, they have not yet established a
firm connection between the mountains’ changes and climate
change, Thakuri said.

He and his team determined the extent of glacial change on
Everest and the surrounding 1,148 square kilometer (713 square
mile) Sagarmatha National Park by compiling satellite imagery
and topographic maps and reconstructing the glacial history.
Their statistical analysis shows that the majority of the glaciers in
the national park are retreating at an increasing rate, Thakuri
said.

To evaluate the temperature and precipitation patterns in the
area, Thakuri and his colleagues have been analyzing hydro-
meteorological data from the Nepal Climate Observatory stations
and Nepal’s Department of Hydrology and Meteorology. The
researchers found that the Everest region has undergone a 0.6
degree Celsius (1.08 degrees Fahrenheit) increase in temperature
and 100 millimeter (3.9 inches) decrease in precipitation during
the pre-monsoon and winter months since 1992.

In subsequent research, Thakuri plans on exploring the climate-
glacier relationship further with the aim of integrating the
glaciological, hydrological and climatic data to understand the
behavior of the hydrological cycle and future water availability.

“The Himalayan glaciers and ice caps are considered a water
tower for Asia since they store and supply water downstream
during the dry season,” said Thakuri. “Downstream populations
are dependent on the melt water for agriculture, drinking, and
power production.”