Curious how volcanologists collect samples of ash? Last week, Alaska Volcano Observatory's Kristi Wallace teamed up with California Volcano Observatory’s Seth Burgess to sample tephra around Fairbanks. Where tephra occurs as thin layers sandwiched between other materials, volcanologists dig into the layers above to expose & remove portions of the ash bed. The ash is then studied in the laboratory & can reveal the age & source volcano of the tephra. #TephraTuesday USGS Volcanoes | Alaska Volcano

Southern California’s Only Active Volcano! 🌋 ✅Follow @peterowenfilms for more nature stuff! Did you know the Salton Buttes are the only known active volcanoes in Southern California? Located along the northern edge of the Salton Sea, these rhyolite lava domes are the youngest volcanoes in the state, having formed just a few thousand years ago. The Salton Buttes were created by the movement of the Earth’s crust along the San Andreas Fault and the Salton Trough, where magma from deep underground