diff --git a/gmtsph-regional.sh b/gmtsph-regional.sh
index 247c376..aaa73ec 100755
--- a/gmtsph-regional.sh
+++ b/gmtsph-regional.sh
@@ -84,7 +84,7 @@ else
 	gmt gmtset \
 	FONT_ANNOT_PRIMARY=8p,Times-Roman,black \
 	MAP_FRAME_PEN=thinnest,black \
-	MAP_FRAME_WIDTH=1.5p \
+	MAP_FRAME_WIDTH=1p \
 	MAP_TICK_LENGTH_PRIMARY=1.5p/1p \
 	MAP_TICK_PEN_PRIMARY=thinnest,black \
 	MAP_TITLE_OFFSET=6.5p \