The Seismic Station IO.EVN at Pyramid EvK2cnr (Everest): 10 Yr of Activity

Abstract This article presents an overview of the first 10 yr of activity of the IO.EVN seismographic broadband station, managed by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS and installed near the Observatory-Laboratory Pyramid, about 6 km from Everest Base Camp (Nepal) at 5000 m above sea level. The IO.EVN station is registered in the International Federation of Digital Seismograph Networks (FDSN; see Data and Resources). It has been in operation since 2014 and played a crucial role during the 2015 crisis following the Gorkha earthquake because it was the closest broadband seismometer to the epicenter. The site is located in a remote area with ideal conditions for noise attenuation and is suitable for recording environmental microtremors and earthquakes in the Himalayas and worldwide. Khumbu Valley (Mount Everest) is one of the Himalayan regions that has not been struck by significant earthquakes (Mw > 7.8) in living memory. Although the analysis of microseismicity deserves further investigation, this article focuses more on the analysis of seismic noise, which was conducted to identify the various weather and climate phenomena affecting the region. In our case, we have found that for the major weather phenomena such as typhoons the main effect is due to the reflection of ocean waves on the coasts, whereas local effects such as rain and wind during the monsoon are more significant as the noise level of waves is probably constant throughout the year. The Pyramid is an important station for weather and climate, and the role of the IO.EVN could prove relevant in understanding climate change in the future.