diff --git a/CMakeLists.txt b/CMakeLists.txt
index f0dde07b58..b50b0338cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -167,6 +167,10 @@ include(${PROJECT_SOURCE_DIR}/cmake/DetectOptions.cmake)
 if(ADIOS2_HAVE_CUDA)
     set(CMAKE_CUDA_STANDARD 11)
     set(CMAKE_CUDA_STANDARD_REQUIRED TRUE)
+    if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES)
+        # default 70 to match Summit V100
+        set(CMAKE_CUDA_ARCHITECTURES 70)
+    endif()
 endif()
 
 if(ADIOS2_HAVE_MPI)