The earth’s crust is a leaky geofluid system where surface trace gas emissions relate to open migration pathways and the presence of subsurface source(s). Seismic activity can open sealed migration pathways leading to trace gas emissions from the surface intersection of the active fault, which may not relate to observable surface fault rupture or offset. After the M7.1 Ridgecrest earthquake, we collected mobile surface trace gas and meteorology data with AMOG (AutoMObile trace Gas) Surveyor, a mobile atmospheric chemistry and meteorology lab, in the Death Valley Park and Searles Valley within 24 hours of the quake, the following week, and after several weeks with air samples also were collected for detailed later laboratory analysis. We found widespread highly elevated CO2 emissions along Panamint Valley including overall elevated SO2 and H2S with strong enhancements around Manly Pass, where aftershocks occurred at the northern edge of the Slate Range and along a trend parallel to Water Canyon. This is in contrast to AMOG data collected in Death and Panamint Valleys in 2014, where concentrations were typical of California desert levels–near ambient and uniform. Significant sulfur trace gas emissions were discovered escaping from the rim of Ubehebe Volcano, last active ~2500 B.P., 115-km north of the Slate Range. Faults appear to play an important role in these geogas emissions, activated by the major earthquake and aftershocks. Further investigations are planned to characterize the system’s return towards quiescence.

Large positive anomalies in lower troposphere methane (CH4) in early fall of nearly every year (2003 to 2015) led to an average atmospheric CH4 growth of 3.06 to 3.49 ppb yr-1 for the Barents and Kara Seas (BKS). At the same time, sea surface temperature (SST) increased from 0.0018 to 0.15 °C yr-1 while sea ice coverage decreased. Large positive CH4 anomalies were discovered around Franz Josef Land (FJL) and offshore west Novaya Zemlya with smaller CH4 enhancement and growth near Svalbard, downstream and north of known seabed CH4 seepage. The strongest SST increase each year was in the southeast Barents Sea in June due to strengthening of the warm Murman Current (MC) and in the south Kara Sea in September. We propose that atmospheric CH4 increase is occurring due to seepage from the petroleum reservoirs underlying the BKS and thawing of subsea permafrost and hydrates which then ventilates to the atmosphere from seasonal deepening of the surface ocean mixed layer and also from “methane shoaling” where currents transport deep water CH4 into shallower waters. Continued strengthening heat transfer by the MC to the BKS will contribute to further warming (with the Barents Sea projected ice-free around 2030) and marine CH4 emissions to the atmosphere.

On decadal timescales, the greenhouse gas methane (CH4) is ~100 times more potent than carbon dioxide. Its abundance is increasing, many of its sources are temperature dependent. The Arctic is the site of the fastest warming globally. Feed-backs between Arctic temperature and CH4 emissions and concentrations need investigation. Unfortunately, available Arctic in situ data are extremely sparse with no marine observations outside summer. Satellite instruments measuring solar radiation reflected from the surface are ineffective in the Arctic. Thus, we leverage satellite data from AIRS, IASI-1, and IASI-2 Thermal Infrared (TIR) spectrometers, which provide year-round, day/night CH4 observations. Available in situ high latitude NOAA/ESRL surface coastal (50-85°N) flask atmospheric CH4 concentrations were compared with satellite data. We find: 1) remote sensing data revealed 150% (IASI-1, mid-upper troposphere) and 80% (surface data for Arctic stations) increases in atmospheric CH4 concentration growth rates between 2010-2014 and 2014-2017 time spans. Global NOAA/ESRL surface concentration rates increased by 90% for the same period; 2) maximum CH4 seasonal emission from the Arctic land occurs in boreal summer, while that from the Barents Kara Sea (BKS) occurs in boreal winter (Nov–Mar). Total annual Arctic Ocean CH4 emissions are preliminary estimated as ~40% of all land emissions North of 50°N; 3) marine emissions are concentrated in shelf areas within ~100 km of the coasts of major Arctic BKS lands; 4) CH4 anomalies over BKS, defined as surplus over its concentration at the North Atlantic area, grew after 2014; 5) the strongest SST increase was observed every year in the southeast Barents Sea in June due to strengthening of the warm Murman Currents and in the south Kara Sea in Sept. Direct in situ CH4 flux measurements during polar night over sea are necessary to test the satellite results.