diff --git a/src/seismic_hazard_forecasting.py b/src/seismic_hazard_forecasting.py
index e79289b..8624179 100644
--- a/src/seismic_hazard_forecasting.py
+++ b/src/seismic_hazard_forecasting.py
@@ -90,6 +90,7 @@ def main(catalog_file, mc_file, pdf_file, m_file, m_select, mag_label, mc, m_max
     from matplotlib.contour import ContourSet
     import xml.etree.ElementTree as ET
     import json
+    from concurrent.futures import ThreadPoolExecutor
 
     logger = getDefaultLogger('igfash')