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Inflation Threshold Forecasts - Method #3 (last 3 months)

This is a third alternative method of forecasting the time when Axial Seamount will reach the inflation level reached before the 2015 eruption started. We have found that Forecasting - Method #1 and Forecasting - Method #2 have not been ideal, so we are trying a third. Method #1 is "noisy" because the de-tided BPR depths include tidal residuals and oceanographic effects; it uses an average rate of uplift from the last 12 weeks. In contrast, Method #2 uses DEPTH DIFFERENCES between two stations (removing the source of noise in #1) to calculate a differential inflation rate; it used an average rate of uplift from the last 4 weeks. This was better, but the time-period for averaging the rate of uplift seems to be too short, so in Forecasting - Method #3, we are averaging the rate of uplift over the last 12 weeks. Hopefully that will give us the best of both worlds. We use the average inflation rate for the last 12-weeks (shown on the Forecasting - Method #2 page) to extrapolate into the future to when the differential level of inflation will reach: (1) the level when the 2015 eruption started, and (2) a level 20 cm higher than in 2015 (which is somewhat arbitrary, but is included because the level of inflation in 2015 was higher than the level reached before the 2011 eruption).  These plots are updated once a day using the latest data from the OOI Cabled Array.


Note: the rate of inflation is variable and so the forecast dates will also vary with time.  The histogram plot below shows the dates where most of the forecasts have fallen.  When the 12-week inflation rate gets very low, forecasts are suspended until the rate returns to higher levels.  Of course, we do not know at exactly what level of inflation the next eruption at Axial will be triggered, but our best guess is that it will be within a year after the 2015 inflation threshold is reached.  We will likely make a more specific forecast when we get closer to that threshold on our Axial Seamount Eruption Forecast Blog.  Programing by Andy Lau, Oregon State University.


Plot of predicted date when inflation will reach the 2015 threshold

Plot of OOI BPR data from the Caldera Center (BOTPT-A301-MJ03F; black curve) showing deflation during the 2015 eruption (left) followed by re-inflation.  If the rate is positive, a blue dashed line extrapolates into the future using the average rate of inflation from the last 12 weeks; middle blue dot is date when 2015 inflation threshold is reached, right purple dot is when a threshold 20 cm higher will be reached. Specifics are included in the legend on the plot.  Click for a larger version this plot.



Histogram of predicted dates

Histogram of predicted dates when Axial Seamount will reach the 2015 threshold, color coded by when the predicted date was calculated.  Predicted dates were calculated based on the average rate of reinflation from the previous 12-weeks, beginning in June 2015.  Predicted dates are binned in months.  Click for a larger version this plot.

Plot of predicted dates vs. date on which prediction was made

Plot of Predicted date that inflation will reach the 2015 inflation threshold (Y-axis) vs. Date on which the prediction was made (X-axis), using the average rate of inflation from the previous 12 weeks, starting in June 2015.  Blue dots are date to reach the 2015 inflation threshold; purple dots are for a threshold 20 cm higher (as in the first plot above). Note predicted dates were earliest when the rate of re-inflation was highest, soon after the 2015 eruption (left side of plot).  Peaks in the curves show time periods when the average rate of inflation slowed significantly (especially in mid-2019), which pushed the predicted dates farther into the future.  Click for a larger version this plot.

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National Science Foundation | The Ocean Observatories Initiative | Cabled Array Observatory


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