In a small bowl, whisk together the blood orange juice and ¼ cup olive oil. Toss with the sliced fennel and season, to taste, with salt and pepper.
In a large skillet, heat the remaining ½ cup olive oil over high heat, until shimmering. Pat the scallops dry and season with salt and pepper. Add the scallops to the skillet and cook until browned on the bottom, about 3 minutes. Turn the scallops over, add the butter and capers to the skillet, and cook until the scallops are cooked through, about 2 minutes.
Remove the scallops to a paper towel lined plate and allow to drain.
Continue cooking the capers until browned and crisp and then remove to the plate with the scallops.
Mound the fennel on a serving platter and top with the sliced blood orange, scallops, capers, green olives and pistachios. Serve immediately.