<div dir="ltr"><div class="gmail_quote"><b style="color:rgb(255,0,0);font-family:arial,helvetica,sans-serif;font-size:large">Post-eruptive landsliding and the organic carbon footprint of explosive volcanic eruptions</b><br><font face="arial, helvetica, sans-serif"><b><br></b></font><b style="font-family:arial,helvetica,sans-serif">Dr. Christian Mohr</b><br><i style="font-family:arial,helvetica,sans-serif">University of Potsdam, Germany </i><br><font face="arial, helvetica, sans-serif"><i><br></i></font>Fjord landscapes sustaining old-growth temperate rainforests not only feature some of the most spectacular topographic relief; they are also major sinks of organic carbon. Prior work has focused on the effects of past glacial processes in these landscapes, but we still have much to learn about contemporary rates of erosion and the involved organic carbon. In this context, the role of episodic disturbances—particularly volcanic eruptions—in mobilizing sediment and highly organic soils and vegetation mats is largely unknown. <br><br>Following two recent explosive volcanic eruptions in Chile, erosion and organic carbon entrainment rates by shallow landslides and floodplain erosion in forests smothered by thick tephra layers were at least one order of magnitude higher than in undisturbed forests nearby. A distinctly clustered distribution of landslides is consistent with slope-stability models that capture opposing trends of root decay after deforestation and successive regrowth. These competing trends indicate a window for maximum hillslope instability somewhere between four to six years after the eruptions. <br><br>Given an recurrence interval of roughly 275 years for major explosive eruptions in the Andean Southern Volcanic Zone, the combined long-term annual carbon release from hillslopes and floodplains into the fjords is around 3-13 tC/km2. Yet, this average does not capture the pulsed nature of sediment and biomass flushing observed in the first few years following the eruptions. Therefore, Patagonian temperate rainforests may tip from carbon sinks to carbon sources, if impacted by tephra cover. In this context, soil burial plays the decisive role. Explosive volcanic eruptions may be previously overlooked generators of terrestrial organic carbon pulses into the Patagonian fjords, and the delayed hillslope response to these eruptions adds to the portfolio of protracted geomorphic hazards.<br><br><font color="#000000" face="arial, helvetica, sans-serif"><br></font><b style="font-family:arial,helvetica,sans-serif"><div style="display:inline"><div style="display:inline">Thursday, March 21st</div></div></b><b style="font-family:arial,helvetica,sans-serif">, 2019</b><br><b style="font-family:arial,helvetica,sans-serif"><div style="display:inline"><div style="display:inline"><div style="display:inline"><div style="display:inline"><span class="gmail_default">Presentation: 10</span>-<span class="gmail_default">11a</span></div></div></div></div></b><b style="font-family:arial,helvetica,sans-serif"><div style="display:inline"><div style="display:inline"><div style="display:inline"><div style="display:inline">m</div></div></div></div></b><b 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Room (204)</b><br><font face="arial, helvetica, sans-serif"><br></font><span style="font-family:arial,helvetica,sans-serif">*Note: Please arrive </span><u style="font-family:arial,helvetica,sans-serif">~5 minutes early</u><span style="font-family:arial,helvetica,sans-serif"> and </span><u style="font-family:arial,helvetica,sans-serif">bring photo ID</u><span style="font-family:arial,helvetica,sans-serif"> for airport-style security </span><span style="font-family:arial,helvetica,sans-serif">measures now in place at the USGS building.</span><br><font face="arial, helvetica, sans-serif"><br></font><span style="font-family:arial,helvetica,sans-serif">Thank you,</span><br><span 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style="font-family:arial,helvetica,sans-serif"> </span><span class="gmail-m_-7703268767022535975m_3485580163267890923m_6379896745468811886gmail-m_2598911593378937838gmail-m_6012531963078816722m_-5782273628114337997gmail-m_379840814356139590m_-9045602766160175400gmail-m_-360571178749533081m_-7901947052896849077m_3236526448127864107m_-3288477519130982688gmail-m_-6155609227449741943m_-3925818064261910720m_-5728151607603070216m_-3855843289950950678gmail-m_-2556572378480268931m_4008722731611885424m_-755589242917698039m_-1297155280521909378gmail-m_1025391756630084150m_7066959450357385387m_-8586038301793833330m_2174399009776966998gmail-m_3536024389969136014gmail-m_6564323528617604720gmail-m_-3202867471772006187m_-3474394390109531423m_-6180755618559776416m_-6692829955733685287gmail-m_-1920778670233885335gmail-m_2928417918433606341m_548290485840828435m_3628773897655229900gmail-m_7446487874202752399m_-8264889372741220741gmail-m_5431511284334585236gmail-m_-1882990626170291808m_9106775657748341738gmail-m_6925426022411937115m_7055967733504661449gmail-m_-8968070735390492279m_4896026561608388806gmail-m_3918809983636524111m_7068817575649352729m_-6172873775242136948gmail-m_-4303968599703518853gmail-m_2043882230405221244gmail-m_2480559937188047531m_-1887565490609744462m_8131614935401267798m_6252585815979993878gmail-m_-5616756539997506461gmail-m_3957397034944864967gmail-m_-5590660146057455466gmail-m_2010942344340859242gmail-m_4771098111974711889gmail-m_337406015407620904gmail-m_-5330926199930091226m_647861723187015620gmail-il" style="font-family:arial,helvetica,sans-serif"><span class="gmail-m_-7703268767022535975m_3485580163267890923m_6379896745468811886gmail-m_2598911593378937838gmail-m_6012531963078816722m_-5782273628114337997gmail-m_379840814356139590m_-9045602766160175400gmail-m_-360571178749533081m_-7901947052896849077m_3236526448127864107m_-3288477519130982688gmail-m_-6155609227449741943m_-3925818064261910720m_-5728151607603070216m_-3855843289950950678gmail-m_-2556572378480268931m_4008722731611885424m_-755589242917698039m_-1297155280521909378gmail-m_1025391756630084150m_7066959450357385387m_-8586038301793833330m_2174399009776966998gmail-m_3536024389969136014gmail-m_6564323528617604720gmail-m_-3202867471772006187m_-3474394390109531423m_-6180755618559776416m_-6692829955733685287gmail-m_-1920778670233885335gmail-m_2928417918433606341m_548290485840828435m_3628773897655229900gmail-m_7446487874202752399m_-8264889372741220741gmail-m_5431511284334585236gmail-m_-1882990626170291808m_9106775657748341738gmail-m_6925426022411937115m_7055967733504661449gmail-m_-8968070735390492279m_4896026561608388806gmail-m_3918809983636524111m_7068817575649352729m_-6172873775242136948gmail-m_-4303968599703518853gmail-m_2043882230405221244gmail-m_2480559937188047531m_-1887565490609744462m_8131614935401267798m_6252585815979993878gmail-m_-5616756539997506461gmail-m_3957397034944864967gmail-m_-5590660146057455466gmail-m_2010942344340859242gmail-m_4771098111974711889gmail-il">Seminar</span></span><font style="font-family:arial,helvetica,sans-serif"> Committee </font><br><font face="arial, helvetica, sans-serif"><br></font><div style="font-family:arial,helvetica,sans-serif;display:inline">Ben </div><span style="font-family:arial,helvetica,sans-serif">Mirus - </span><a href="mailto:bbmirus@usgs.gov" target="_blank" style="font-family:arial,helvetica,sans-serif">bbmirus@usgs.gov</a><br><span style="font-family:arial,helvetica,sans-serif">Josh Rigler - </span><a href="mailto:erigler@usgs.gov" target="_blank" style="font-family:arial,helvetica,sans-serif">erigler@usgs.gov</a><br><div><div><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div class="gmail_quote"><div><div><div class="gmail_quote"><div><div class="gmail_quote"><font face="arial, helvetica, sans-serif">Oliver Boyd - <a href="mailto:oboyd@usgs.gov" target="_blank">olboyd@usgs.gov</a></font></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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