GPS Data Show How Nepal Quake Disturbed Earth’s Upper Atmosphere

[MorningSong]

This article might show up via the NASA Bot, and it probably needs to be put into the "Earthquakes..." subforum, but I didn't want this important info to get lost in the rolling Bot threads....

May 1, 2015

GPS Data Show How Nepal Quake Disturbed Earth’s Upper Atmosphere



The April 25, 2015, magnitude 7.8 Gorkha earthquake in Nepal created waves of energy that penetrated into Earth's upper atmosphere in the vicinity of Nepal, disturbing the distribution of electrons in the ionosphere. The ionosphere is a region of Earth's upper atmosphere located from about 37 miles (60 kilometers) to 621 miles (1,000 kilometers) above Earth’s surface. These disturbances were monitored using signals transmitted by the Global Positioning System (GPS) that were received by a science-quality GPS receiver located in a neighboring region to Nepal.

The disturbance measurements, known as vertical total electron content (VTEC) (depicted in blue in the upper panel), have been filtered using processing software developed by NASA’s Jet Propulsion Laboratory, Pasadena, California, to show wave-like disturbances (circled in red) in the distribution of electrons in the ionosphere. The waves have periods of between two and eight minutes in length. The disturbance measurements following the earthquake rupture are circled in black in the lower panel. The colors represent the relative strengths of the earthquake-induced ionospheric disturbances as captured by the GPS signals, with red being high and blue being low.

The data show that after the initial earthquake rupture (indicated by the vertical black line) it took about 21 minutes for the earthquake-generated ionospheric disturbance to reach a GPS station (LHAZ), located about 400 miles (640 kilometers) away from the epicenter in Lhasa, Tibet, China. The station is hosted at the Tibet Autonomous Regional Bureau of Surveying and Mapping Institute. The site collects both GPS and GLONASS (the Russian global navigation satellite system) data at a rate of 1 Hertz and is part of an international scientific collaboration known as the International GPS Service (IGS) (http://igs.org/igsnetwork/network_by_site.php?site=lhaz).

Scientists study ionosphere-based measurements caused by natural hazards such as earthquakes, volcanic eruptions and tsunamis to better understand wave propagation in the upper atmosphere. The disturbances caused by earthquakes help scientists develop new first-principle-based wave propagation models. These models may become part of future early warning systems for tsunamis and other difficult-to-detect natural hazards.

The data may be accessed at: ftp://cddis.gsfc.nasa.gov/gps/data/h...15/115/15d/06/.

Image Credit: NASA/JPL/Ionosphere Natural Hazards Team

Last Updated: May 2, 2015
Editor: Tony Greicius

PS: Mods, could we have a " EQ discussion" sub-subforum in the EQ subforum so things don't get submersed by the bot?

[Johnnycomelately]

Came looking for a Nepal thread to add a vid to, found this tantalizing story of a huge electric effect
from a big earthquake in Nepal a few years ago.

I suggest we make this thread the main Nepal thread, and so add this beautifully filmed and produced vid of several difficult and dangerous travels in high country.

The trek in to the three villages in Limi Valley (total pop ~1500) uses light trucks where possible, between which they walk and their precious vaccine cargo is carried by mules. The mule owner/handler bails with his critters before the group reaches the final of several 5000m passes, fearing injury to the mules. They had begun struggling in the deepening snow, risking breaking legs.

The other main travel story was of a heavy transport truck driver doing his regular scheduled supply run. Crazy scary cliffside roads, “I lost three friends here”. He had been a good student, but as the oldest male child he had to go to work at 15 when his father died, to support his family.

Some cultural content, including a bit near the end about the Buddhist monastery in the valley, and how it dominates life for the villagers.

L = 35:20.

Nepal’s Hidden Limi Valley | Deadliest Journeys

Les Routes de l'impossible

899K subscribers

363,404 views as of Feb 13, 2025. Posted Jan 25, 2025.

“ In the remote northwest of Nepal, the Limi Valley, nestled behind peaks towering over 6,000 meters, becomes inaccessible during the winter. Cut off from the rest of the world, it relies on the determination of a few men and women to deliver vaccines and medicines. This journey, spanning several days, combines hiking and the use of 4x4 vehicles. However, mule caravans often prove to be the most reliable means of transport in the challenging terrain.
These western regions, among the most isolated in the country, require traversing treacherous paths where every crossing teeters on the edge of disaster. Nagendra, behind the wheel of his truck, ventures dangerously close to the abyss, ready to take any risk to make his deliveries and provide for his family.”

Source: https://youtube.com/watch?v=02EkKGt1Efo