From e207b44f9d7405585a9deb42b0c04ed220e5e6c0 Mon Sep 17 00:00:00 2001
From: WENZHI HU <116841989+ada-wh525@users.noreply.github.com>
Date: Sat, 24 Oct 2026 19:55:48 +0800
Subject: [PATCH] docs: Document the SeismicModel fs parameter

---
 examples/seismic/model.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/examples/seismic/model.py b/examples/seismic/model.py
index 610f98313c4..3fe094d1341 100644
--- a/examples/seismic/model.py
+++ b/examples/seismic/model.py
@@ -255,6 +255,10 @@ class SeismicModel(GenericModel):
         Velocity in km/s.
     nbl : int, optional
         The number of absorbin layers for boundary damping.
+    fs : bool, optional
+        Enable a free surface at the top of the model (the lower boundary
+        of the last spatial dimension), omitting the absorbing layer there.
+        Defaults to False.
     bcs: str or callable
         Absorbing boundary type ("damp" or "mask") or initializer.
     dtype : np.float32 or np.float64