**Prologue**

In the 1960s the first global network of seismic stations was in place. In the ~ six decades since then, much data has been collected.

This study examines the earthquake data since the 1960s by decade according to magnitude. Graphs are presented for magnitudes 5.0 to 5.9, 6.0 to 6.9; 7.0 to 7.9, 8.0 to 8.9, and 9.0 to 9.9.

All data is from the USGS Earthquake Archives, https://earthquake.usgs.gov/earthquake, retrieved January 2017.

## Graphs

**Earthquakes by Decade: Magnitude 5.0 to 5.9**

The data for the first decade, 1960 to 1969, is not reliable probably because the global seismic network was not yet capable of picking up all global earthquakes in the magnitude 5.0 to 5.9 range. But the data for this magnitude from the 1970s onward is reliable. The graph has a positive slope, showing an increasing trend for the number of earthquakes over time. However, six decades of data relative to geological time is still a small sample size to base a conclusion on. But it is the only global data we have.

**Earthquakes by Decade: Magnitude 6.0 to 6.9**

The graph has a positive slope, showing an increasing trend for the number of earthquakes in the magnitude 6.0 to 6.9. Again, six decades of data relative to geological time is still a small sample size to base a conclusion on. But it is the only global data we have.

**Earthquakes by Decade: Magnitude 7.0 to 7.9**The graph has a positive slope, showing an increasing trend for the number of earthquakes in the magnitude 7.0 to 7.9. Again, six decades of data relative to geological time is still a small sample size to base a conclusion on. But it is the only global data we have.

**Earthquakes by Decade: Magnitude 8.0 to 8.9**

The graph has a positive slope, showing an increasing trend for the number of earthquakes in the magnitude 8.0 to 8.9. Again, six decades of data relative to geological time is still a small sample size to base a conclusion on. But it is the only global data we have.

**Earthquakes by Decade: Magnitude 9.0 to 9**

This graph does not show any trend for the number of earthquakes in the magnitude 8.0 to 8.9. Again, six decades of data relative to geological time is still a small sample size to base a conclusion on. But it is the only global data we have.

#### A comparison of graphs for magnitudes 5 through 8, 1960 to 2016

An increasing trend for all four magnitudes of earthquakes, 5.0-5.9, 6.0-6.9, 7.0-7.9, 8.0-8.9, can be seen over the past ~six decades.

## Data Tables

The data for the seven years of the current decade so far is shown above, and is used to to project an approximate expected total for the decade 2010 to 2019.

The earthquake data for the seven years of 2010-2016 is used to calculate an average number of earthquakes per year so far this decade. That average is used to calculate a predicted number of earthquakes for the decade 2010 to 2019.