Seismic Eruption - forecasting future earthquakes

“Since my first attachment to seismology, I have had a horror of predictions and of predictors. Journalists and the general public rush to any suggestion of earthquake prediction like hogs toward a full trough.” - Charles Richter (1977)

Whoever wishes to foresee the future must consult the past; Turn to you partner and discuss this statement What does it mean? Provide an example where it applies Could this statement connect to earthquakes? How?

Developed with support from the Smithsonian Developed with support from the Smithsonian. Maintenance for this software has come from the National Science foundation through the IRIS Consortium. Windows-based freeware Plots both earthquakes and volcanoes through time on maps Earthquakes are circles on the map with color representing depth and size showing magnitude Volcanoes are triangles on the map with size showing magnitude and color show eruption type. The plotting of events is controlled with CD-style controls, which allow you to speed up, slow down, pause and rewind the data. The controls Earthquake catalogue 1960 - present (updateable) from NEIC Too Much detail - Worldwide ≥M 5.0, US ≥ M4.0, CA ≥ M3.0

Once students have selected a region they wish to explore they begin collecting data by for the number of events of various sizes that occur through time. This data is collected by stepping through the catalogue using a M 0.5 interval (say M 9.0 - 3.5) which can be controlled by setting the EQ Cutoff tool and the counter

Additional functionality Has numerous preset views, Investigate global and regional geohazards Explore Plate Tectonics via cross-sectional perspective views of earthquake locations Is also very customizable Make your own map Terrain files Event files Which allow you to zoom into pre-selected regions to

Looking for seismicity patterns Steps: Select a region of the world that is of interest to you by “making your own map” Interrogate the EQ catalogue to determine the number of various sized events that occur annually for your region. (Use M 0.5 intervals) See Tab 9 Plot this information on the graph provided (or use Excel)

Questions Do you see any patterns or trends in earthquake occurrence in your region? Can you think of any reasons why the trend may be “flat” for small magnitudes? What is the likelihood that an earthquake of magnitude 7.0 or greater (which can cause severe damage) will occur in the next year in your region? How might this information be useful to society? Is there a risk for forecasting earthquake likelihood using a data set that only goes back to 1960? Where students present to each other on the following guiding questions…

Questions What is the likelihood that an earthquake of magnitude 7.0 or greater will occur in the next year in the 2 regions? How might this information be useful to society? Is there a risk for forecasting earthquake likelihood using a data set that only goes back to 1973? Where students present to each other on the following guiding questions…

Are the numbers of earthquakes in the smallest and largest ranges consistent with the trends in the other regions? Can you think of any reasons why the trend is “flat” for small and also large magnitudes? But does allow you explore the limits of the data set and extrapolation of the data set. What does it physically mean to extrapolate this data set over time. This point on the trend shows on average that a Magnitude 8 occurs once every ten years and if we look back to the data table we can see this… The December 2004 Sumatra event is not shown we can extrapolate the data to see an occurrence rate of 1 M 9.0 event every 67 years. However you might ask students to comment on the fact that our data also suggests that such an earthquake would be expected every 1000 years in CA/NV.

2002 National Seismic Hazard Map

Earthquake Hazard Analysis Although we can’t predict earthquakes (in the sense of predicting a specific time, location and magnitude)… Earthquake Hazard Analysis Global Seismic Hazard Map We can estimate the probability that a given amount of ground shaking will occur during a given period of time at some location.

Summary Accommodates student interests by allowing them to define the temporal & spatial limits of their study. Simple, easily acquired data set Explores the broad topics that lead to a general understanding of frequency and distribution of earthquakes Engages students in the process of science  Making observations Collecting empirical data Exploring the limitation of the data Organization, graphing and analyzing the data Developing logical arguments to support conclusions Skeptical review of other students’ work Includes a different set of process skills that differentiate it from an S-P activity

Guiding Content Questions Where do earthquakes occur? How frequently do earthquakes occur? How frequently do various sized earthquakes occur? How does regional tectonics affect distribution and frequency? Can past history of Earthquake occurrence “predict” future occurrences? In this activity, students can work either individually or in groups to explore some of the key aspects of seismology that an educated citizenry should grasp. These topics include: Earthquake occurrence Frequency Frequency for various sized events The impact of regional tectonics And of course the extremely popular topics of Earthquake prediction.

Skills Emphasized Making observations Creating a semi-log graph Interpreting and identifying patterns in data. Drawing conclusions Prediction and hypothesis testing Writing a lab report or creating a poster In addition to the content, the lab places a strong emphasis on the skills an processes of science including..